May be worth giving Stuart a ring here in Hailsham and he's very good and very cheap. I can give you his number if you want it?
I changed the cambelt kit and waterpump on my classic a month ago or so and to be honest it's not that bad, I didn't need any special tools at all and took me about a day (I know some people on here can do it quicker but I like to take my time).
It cost me in total best part of about £300 for parts, which was cambelt kit (idlers and tensioners as well as belt), waterpump and thermostat.
Yes something could go catastrophically wrong if you get the timing completely wrong but to be honest, line up the cam pulleys and you should be fine.
PM me if you need a hand or anything
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PS.. The hardest and longest bit was keeping the cam pulleys in the correct place while putting the new belt on.