i think if you look at your licence closeley you can tow behind a 7.5 ton truck upto a gross train weight of upto 12 tonne without a lgv licence, i have seen a landy on the back of a transit and it does not look nice and i would certainly not attempt to drive one
i use a 7.5 ton truck and it is far cheaper to run than my shgun and trailer in both fuel, and road tax, i can sit at 65-70mph in comfot and not worry about what a trailer is doing,
if you are prepared to tax/insure another vehicle then the only way to do it is 7.5 ton and get your license