While the torque-feed angle-armed spanner is an excellent tool for the job, it's a bit specialised. I worked at a dealership, and found that an offset-handle double-action ratchet wrench did just as good a job at half the price.
Ask at Halfords, but be specific: they may try to sell you the single-action one, but it won't do the job.
Patrick Clement, August 2009