IMHO I wouldnt even think about putting that much weight off the back end of a 110 - its a recipe for something going wrong - light front end, welds cracking over corrogations, and awkward to get into the rear...etc etc......the only way id carry them on the Landy is in the load bed - (if its a truck cab) and even then that would not be ideal.
Trailer wise the normal Sankey is way too short - the Sankey 1 ton Rapier Missile Supply Trailer is long enough - but its heavy and very tall for loading.
The best Trailer by far is the Ifor Williams GD84 -you can pick up a good used one for about £600 - The single axle would be best (less bounce, less tyres) with the uprated hubs and 16 inch rims - you can move the wheel arches up a bit and fit the same tyre size as the 110 - so spare tyres arent an issue.
My KTM Adventure fitted on mine with about 10 inches to spare at the back. - much better and stronger (and more useful) than any bike trailer IMO, with the drop down mesh loading ramp its easy to load/unload.
Its also alot lower than the Sankeys - lower centre of gravity and with the taller 16 inch tyres has enough ground clearance to be towed off road - The best hitch to use is the NATO 3.5 ton jaw/ring arrangement (one side locked- other rotating)- you can get the bits from Ifor Williams -or good trailer shops.
These may not be the cheapest but they are the best - thats why Land Rover used GD64's on there 50th anniversary global trek.(see link below)
I looked at buying the running gear and welding up the body myself - ended up about the same price - easier to buy a good used one.