I have no experience with the HB511, but I have two Ifor Williams trailers and they are fantastic bits of kit. Do keep a very good eye on security, though. One of our trailers, a 10' x 5' dropside job, was stolen by people who cut the hinges off a gate, drove across two fields, and smashed the wheel lock and the hitch lock off the trailer.
Fortunately it was insured with NFU, who are brilliant, and we had a replacement within a week or so.
