I think the £55 for tracking is probably cheap, but will it be done properly? Not straight forward on a Spit with swing arm suspension.
I would invest the £55 in a tracking plate.
http://www.amazon.co.uk/Gunson-G4008.../dp/B0012M9KEC
It's not as good as the original tool I used to have which was stolen... (BASTARDS) But when your car setup is somewhat non standard (drastically lowered?) it allows you to get the optimum settings without a data book and very simple to use.
I first came across this type of gauge at Charlie Oats garage on the A6 at Yelland. They used to assemble new Lotus 7's, Elans, Europas and other Lotus's, it was their only way of setting the front and rear tracking accurately.
You simply drive or push the car straight over the plate on reasonably flat level ground. If the needle moves it needs adjustment in or out, it tells you which. It works just as well on front and back, either side. It automatically compensates for camber. All it does is measure the tyre scrub, you want zero tyre scrub.