I wouldn't touch the Warco with a ten foot pole. The Axminster is a better machine but as Woody says the design of the variable speed belt system is not the best on these machines.
If you are going to spend £500 then you need to spend it wisely on something you will not come to regret later.
The CL3 although an equally primitive design is, in my opinion, far better than the other two and as Derek says you can easily, if at some cost, upgrade it to VS later.
You will not get a new, good quality, full size lathe with electronic variable speed for £500. You need to either increase your budget or decide which you can do without, a 36" bed or VS. You are not going to get a quality machine with both in that price range
