HI Andy,
I would start with a few screwdrivers , your normal sized flat screwdriver for electric plugs and a phillips/posidrive are always useful for screws on sax key guards, some smaller screwdrivers, a spring hook, a pad slick, some smooth jawed pliers, a spirit lamp should get you started. If your working on saxes then a half decent leak light can be made using a mobile phone charger, some bell wire and a 12v 4W indicator bulb and socket (available from Maplins) An oil bottle with a needle applicator is a great bit of kit (60p on ebay) I use these for oil, flux for soldering, penetrating fluid. Another tool I tend to use for all sorts including getting underneath sax resonators to remove pads from the key cups is an old fashioned butter knife. A jewellers saw is a must if you are making parts. I would buy tools as you need them as opposed to forking out a bundle and not using them.
There are good sources for tools:
www.ferreestools.com - these tools are available from
www.windcraft.co.uk
www.jlsmithco.com
www.boehmtools.de
www.hswalsh.com
and supplies
www.windcraft.co.uk
www.windplus.co.uk
www.prestini.de
www.musiccentre.it
www.ferreestools.com
I would wait until you've been on your course in Wales before rushing out any buying all the tools in the saxophone repair section of these books. A lot of them are not fit for purpose IMHO. I bought a few sets of sets of different tools and haven't used a load of them, but have utilised them by turning them into tools I can use.
If you get the Reg Thorpe Book, theres a section in there on tool making
PM me and I'll sent you some stuff.