Ditchit,
For your first couple of plans-built models I'd refrain from buying a scroll or band saw, not really worth the money unless you are going to do a LOT of plans building, especially with prices being what they are in the UK.
The thin parts, up to about 5 mm, you should be able to cut out with an x-acto knife (a fine modelling knife, similar to a scalpel). Thicker than that, use a coping saw, which is a fine cutting frame saw with a thin blade. For fast straight cuts, use a razor saw, which kind of looks like a small meat clever. Another good tool to have on hand is a carpenter's utility knife. These use a fairly large, reversable razor blade. All of these tools are available from your local DIY shop, and shouldn't cost you more than a dozen Nuggets all together.
For (in my opinion) a good article on what tools to buy to get started and how to set up a workshop, see Setting up a Basic Workshop at
http://webpages.charter.net/rcfu/Beg...cWorkshop.html
For a few good plans to get started in scratch building, see the plans section at the Charles River Radio Control Club
http://www.charlesriverrc.org/articles.htm
Also, check your news stand for copies of Aeromodeller International. It always has lots of good tips on plans building and usually includes a full sized plan as a centre spread. It's too bloody expensive for me to buy over here, but it's relatively cheap on your side of the pond.