Provided that you have the necessary documents that you've already mentioned above, plus the registration documents, there's no requirement to do anything special for a visit of upto 6 months.
Surpringly enough, there's a "6 month rule" in the UK just as there is in Turkey but it's not so strenuously enforced. As the UK Police in some areas have the occasional purge on foreign registered vehicles it's worthwhile keeping hold of your ferry or Channel Tunnel ticket. This will act as proof of entry date into the UK for the vehicle.