Well thank you to everyone that has responded with some very helpful details and advice! It is refreshing in todays age that there are so many people willing to help a stranger.
So very interesting and complicated advice about trailer weights and allowances....I can see that it is a UK drivers nightmare to tow a trailer! The trailer that I was interested in from the earlier link is a 3500Kgs MGW but i would not be loading it up that much, my car as about 2500Kgs at a guess and the items of furniture probably couldn't weigh in any more than 1000Kgs max.
Regarding Ano offer to buy his van, thank you but I don't think that would be the most cost efficient solution for my situation as it will be a one off event. If the trailer is a no-go due to French road regulations then as suggested I will rent a van for 5-6 days from Toulouse area.
@Mint regarding your request, it is very possible and likely that I can assist you, but I just don't know exactly when. Definitely i will be travelling with an empty trailer or van from Toulouse to UK. But more likely to be in the Spring now I think. You can PM me your contact details (e-mail) and we can discuss further the pick-up point and the drop of point in UK.
In fact I think it would be great if there were a Sticky thread with people listing any journeys that they are planning to and fro the UK and possible options of shared spaces and shared costs. Sounds a potentially good idea subject to limited liabilities etc.
Thank you once again to all that have responded.