Thanks everyone

- the information provided has helped me mull over the problem & I think that I have a way forward. To sum up my view on the suggestions:
Front tow ball - I don't think this will help. Although it will improve the turning circle it is still too tight if cars are parked opposite my drive.
Block & Tackle - too much rope, too many knots!
Electric Winch - one you get into the nitty gritty of the right winch (pull 30m at 4m per min line speed) it gets too expensive.
Block & eye bolts - this would result in me pulling a rope with the car across a public pavement.
Move to a new house - just have!

Store Rib somewhere - when I get a bigger one.:d
Sell Rib - definately not.
quad bike/tractor/motor mower - I wish...
That then leave me with two options to persue & I am now watching e-bay looking for a bargain.......
1 - Electric Caravan Mover
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=005
I have set a budget of £250 for this project & I have seen these go for £200 but as they are heavy I need to wait for a local one to come up as the postage costs would be high. If not then it will be....
2 - Winch Type Caravan Mover
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=016
I'm pretty sure that, as the boat is quite light, that it will handle the gradient & the gearing should get me there pretty quick.
Once again - thankyou all for you suggestions.
Cheers - Paul H.