I asked this a few months back mate. Here's one of the answers
#rider
One word of advice on exporting is let the buyer arrange all shipping and customs clearance (the shipping agent usually provides this service). Kingstown are one of the largest USA to UK or vice versa shipping agents. Otherwise you'll be in a whole load of pain from insurance cover (1% of value) and any damage or theft from the car (that happens a lot on cheaper RORO shipping, its less likely to happen if shipped in a sea container but it still does happen) during the transit period.
I'd advertise on ebay.com, facebook and their main classics site classiccars.com
My Mustang Fastback shipped over from the USA with Kingstown, nothing but praise for their service. You have to be on the ball though with getting all customs forms and documents to the agent in time and authority duty payments made (customs won't clear until that is done) for a quick turnaround. Each additional day beyond the two they give you in bonded warehouse racks up charges at an eye watering rate. There is no messing around time allowed, if any is required then that costs money.