Yeah just looking for it now, is that VOSA information in postable format?
Sorry Ian, only just logged back on and read through the thread. The info I was given was by phone, talking to one of VOSA's 'enforcers'. They're actually quite helpful and, certainly the one I spoke to, know what they're talking about.
Basically Paul_C says it about right, particularly about the bit regarding law in the UK preventing things, not enabling them - it boils down to this, pretty much:
The MAM of the trailer isn't relevant to the vehicle, only to the trailer and to the licence the driver holds.
To really spell it out;
If:
1. The driver is licensed B+E...
AND
2. The actual mass of the trailer and load combined at the time of an alleged offence is less than the plated towing capacity of the tow vehicle...
AND
3. The total mass of trailer, load and towing vehicle doesn't exceed the gross train weight (largest number on the VIN, usually) of the towing vehicle...
AND
4. The actual mass of the trailer and it's load combined doesn't exceed the plated MAM of the trailer.
Then
NO OFFENCE is committed. If you don't comply with any one of the above then an offence IS committed, you WILL be reported for it and likely you'll get a fine and points and won't be able to complete your journey.
[important bit]
I'd seriously encourage anyone who is in any doubt about their legality to tow to phone VOSA and speak to them before towing - it'll take a lot less time than arguing the toss with them at the side of the road when you're in the wrong because you didn't know the facts.
[/important bit]
Some other examples:
1. Just because I have a hoody doesn't mean I mug old ladies and hang around bus shelters smoking regals and hash.
2. A 1.8 freelander can break the speed limit (just), but you don't see plod and VOSA pulling
all of them for speeding (many of them are already broken down due to HGF or unbelievable gayness and, while the book figures suggest they'll break 70, they're obviously going nowhere!)
3. Just because I have a trailer which
can be laden to exceed the limits of the current towing vehicle, doesn't mean I'm going to, any more than I am going to overload my 1 tonne single axle tipper just because I can tow 3.5 tonne with my Defender.