Bristoe, there is something none of us has mentioned yet.
Here in NSW the Rural Fire Service runs saw courses pretty much encompassing all one needs to know about the use and maintenance of a chainsaw, and I would bet London to a brick that similar agencies in your area would do the same. They generally have a reasonable selection of saws to play with and it would give you the opportunity to see what suits you.
And as some have mentioned, higher octane fuel does make the saw start and run easier, I use 98 and run the mix at 50:1...it also pays to run decent bar oil in the saw, a lot of the commercial cutters around here mix the bar oil with used motor oil, I refuse to do so as I only use 20 litres of bar oil for the season so the cost is negligible in the scheme of things.
