Try Kingstown Shipping (
http://www.kingstown-shipping.co.uk/). That company ships from Vancouver, Toronto and Montreal into Thamesport (the South of England) or Rotterdam (Netherlands). The cost will be at least US$2,000 for shipping in a container plus a separate marine insurance contract.
Getting the car re-registered in the UK should be fairly straightforward. A well maintained car should pass the Ministry of Transport (MOT) test without difficulty. The UK emissions test for an older car is visual only - i.e. no clouds of black smoke. Your left hand drive ("LHD") lights will dip the "wrong" way for the UK but a sympathetic MOT tester will help you to tape over the offending part of the lense before the test.
Customs duty is about STG£50. In addition value added tax ("VAT") is charged at 17.5% of the value of the car. I don't know whether you might be exempt from this if you don't intend to keep the car in the UK.
Ultimately, you may not want to sell your car in the UK as although prices are higher than in North America (typically STG£15,000 to STG£25,000 depending on condition) your car would be marked down for being LHD and it is very much a buyer's market in the UK. I can't speak for prices in continental Europe and you may do better there. Maybe Cees or some of the members living in Germany or France could give you an indication as to selling prices in their markets.
The rules to register your car will differ in each European country. I think that the UK may be amongst the least bureaucratic but you should check out the rules in each of the most likely markets. VAT is a European Community tax and although the rates may differ between European countries I would expect it to be payable wherever you choose to register the car. One exception is Switzerland which is not a member of the European Community.
Hope this is some help.
Regards
Andrew
1969 280SL
1966 230SL (currently on the MV Ever Deluxe due in at Thamesport tomorrow!)