Hello Andrew
How deep is your wallet?
If shallow, then call in the professionals if you need your boat moved occasionally.
If deep, then, if you are a member of the RYA, you can download their booklet "TRAILING AND ROOF RACKING THE RULES AND REGULATIONS" from their website, last updated 12/09/2012.
Their very comprehensive guide should answer most, if not all, of your possible questions, about the subject, including the key pertinent facts that the maximum permitted towing width in the UK , INCLUDING SIDE PROJECTIONS, is 2.9m [9ft6in], and that "Trailers in excess of 3,500kg laden weight must have fully powered brakes operated by the braking system of the towing vehicle." For your info, my P27 trailer weighed in at 640kg inc spare wheel & docking arms, leaving only 2860kg (6,300lb) for the boat itself...ie no way that your P275 + trailer will gross under 3,500kg
Another, more generic, source of info about all aspects of trailers and towing is
http://www.ntta.co.uk/ .
RM Trailers in Hampshire have made many trailers for Seal & Parker owners over the years, and the Owner of the Company used to have his own P27 or P275 on a road trailer, so could be worth a call...
sincerely
Geoff Sheddick
Parker 27/146 "Stroller'
Geoff Sheddick
Parker 27/146 "Stroller'