Customs Agents for importing Van

[Cornemuse]

Hi everyone. We bought a left hand drive T5 earlier this year as we are doing a lot of driving on the continent. Just about to head into the murky and vague task of officially registering it here in the UK. Apparently the first step is finding a Customs Agent. Can anybody recommend one? Or has anybody been through the whole process and give us any advice?
Best
Stuart