Plusgas and more plusgas. Impact driver and bits, Medium hammer and a decent set of spanners, drivers, socket set, breaker bar, multi tester, digital camera, masking tape, waterproof pen, Sealable bags, cable ties and assorted pliers......... to start.
Don't go for cheap tools as they will be bad. I quite like the Halfords Professional range (I cant afford Snapon/Teng) Keep an eye out for new sets on evilbay (I am sure people nick them and sell them!) or on the Halfords site as they often have half price sales.