Many people recommend Bestek near Crawley. I think if you tell him want you need he will sort it. I think he will also do a swap for a good price for your original one but don't quote me on that!
Make sure the chokes are off, their next to useless on DCOEs. All they did was flood my old car, I was advised don't use it and just press throttle 3 times then crank.
my last correspondence with DVLA was via 'online chat', I found this useful and gave me an exact path to follow, may save some time and angst as to where exactly to send to, just a thought and you can save the conversation just in case.
Hi Simon
Glad to see you are on the road to recovery mate... seems only like yesterday since we were sat in B&Q car park up in Scotland repairing your throttle cable Hope to catch up soon mate