I'd like to get two torches. They both have clones on Amazon.co.uk which look very similar apart from the logo. However, I am concerned they have a less capable LED, which obviously will affect the brightness.
Let me address your last question first:
Finally, I'm looking to get a really decent 16850 battery, but I don't want to worry about any maintenance or gotchas. Am I right in saying that I won't need to worry about things like the charge getting too low or the memory effect on this one?
"A really decent 18650 battery" will almost certainly cost more than either of the flashlights that you are planning to use it in... That is not a bad thing, since the flashlights are quite likely a very good (low cost) value. However, please do understand that quality (relatively safe) 18650 batteries are not cheap. Also, you will also need to invest in a quality charger, and most of us on this forum would probably recommend a simple (cheap) multi-meter to measure voltage.
In other words, using Li-Ions cells safely, can require some extra effort. And, in some ways, using Li-Ion cells might almost be considered a "hobby" in and of itself. If you are a professional user (or "high end user") you can simply spend the necessary money on cells and invest in one of the better chargers (there are many to choose from). But, it is much more of a challenge to get by "on the cheap." My brother manages to do it, but he already had a quality RC charger that he uses to charge his remote controlled cars.
Others may argue that you can purchase a cheap 18650 cell, use a cheap charger, never check voltage... and get away with it. Without a doubt, most people people who choose do do this, do (thankfully) "get away with it." But, however small, the risks of violent out-gassing and flame are real. While quite rare, there are many documented cases to be found both on this site and elsewhere. And, one of the problems with flashlights is that they tend to be strong, air-tight (waterproof), metal tubes... That is exactly what pipe-bombs are. So, in the rare case of an "undesirable" event, the effects can be very dramatic.
I am not trying to talk you out of using Li-Ion cells. What I am suggesting is that you need to be prepared for the fact that you are likely going to be spending far more on battery/charger arrangement than on your flashlight. Once again, that is not necessarily a bad thing. It gives you can opportunity to enter the world of high output flashlights in stages. Once you have made your initial investment in quality cell(s) and charger, you can then take the next step and move up to some of the many quality flashlights that are available.
If you decide to try to "get by on the cheap" then you must accept the inherent risk of extremely inconsistent Chinese quality control, and often very "shady" supply chain. (The cells you purchase might be factory rejects that were once sold as "scrap." People have even found Chinese cells that contain only a tiny energy cell, and large quantities of sand that adds weight to the cell.) But, in truth most of the low cost cells are "real." The main problem is that they are unlikely to live up to their power rating (mAh rating) and you will need to monitor them carefully to detect any early warning signs about their charging/discharging behavior. As I said, my brother has been successful at it (at least so far).
So, having started a the end of you post, let me also address your second pair of flashlights first:
So that's the first pair. For the second pair, it's a toss up between these two:
http://www.amazon.co.uk/UK-DIRECT%C2.../dp/B00QKG7EKC
http://www.amazon.co.uk/Brite-R%C2%A.../dp/B00IEA97N4
Again, they both look the same, but this time, the Brite-R version is more expensive. The Brite-R version uses a "130 Lumen CREE XP-E R2" whilst the UltraFire uses a "350 lumenCREE XR-E Q5 LED". Which do you think will be better and brighter?
Both of these are "Sipik SK68 Clones." Here is the link to the actual
Sipik website. I would say these extremely low cost flashlights are loved by many, and hated by some. They can be found at incredibly low prices at times. While you may occasionally get a "bad" one, most Sellers (whether Amazon, eBay or other) will gladly replacement at no charge, or offer you a discount. I have purchased at least 50 over the years, and have only had trouble with 2-3, and in each of those cases the "problem" was with receiving a 3-mode version when I wanted a single mode version.
These flashlights are quite bright and very practical small flashlights that run on standard "AA" cells. They will also run on "AA" size Li-Ion cells (14500) and are considerably brighter on the Li-Ion, but as I already mentioned, the Li-Ion cells are more difficult to deal with.
One of the previous posts mentioned fake CREE emitters. I think this is less of a problem than was suggested. So far, in my experience, I believe all the Sipik clones that I have purchased did come with CREE emitters. However, despite what is advertised, they sometime come with a different model. For example, you may order the one with an XP-E and get one with an XR-E, or vice versa.
The official CREE datasheets rate the "cool white"
XP-E R2 at 114 Lumens (@350mA) and their "cool white"
XR-E Q5 at 107 Lumens (@350mA). The Sipik website rates the XP-E R3 model at 150 ANSI Lumens, but this is likely measured using a 14500 cells. In any case, however, these are surprisingly bright low-cost flashlights.
Like the previous post, I would recommend that you simply buy the cheapest you can find.
Here's the first pair I'm looking at:
http://www.amazon.co.uk/OxyLED-Flash.../dp/B00NPXCB7E
http://www.amazon.co.uk/gp/product/B00RLQ43K4/
The second of those looks the same, but is cheaper. Will it perform the same though? Its claimed lumen is 450 lumen instead of OxyLED's 500 lumen, but I've learnt not to trust the lumen number as most manufacturers tend to lie somewhat. They both claim to use the same "CREE XM-L T6 LED.
I have no experience with these flashlights, but they look identical to me. According to the official CREE datasheet the "cool white"
XM-L T6 can deliver 692 Lumens (@2000mA). Once again, I would simply purchase the cheapest of the two.