I used a mobile mechanic from Shrewsbury, he was excellent if that's not too far? Was my first box too. My tip is check the payload! Many people don't know theirs but it's easy to be overweight and no one wants to have to unload and find alternative transport if stopped halfway overweight!
Edited to add he also gave me tips and pointers to look out for on several I had been looking at and as a result rather than having several fail an exam the first box passed with only a few minor issues. I'm delighted with mine!