Hello toot, thanks for your input, i think that has made my mind up on the swing bridge, gutted to lose it as i was looking forward to having it on the layout. I think i'll finish building it and stick it up for sale and use the money to buy a couple standard truss bridges.
I've been over London bridge a few times having worked as a sparky all over that area, i don't think my scratch building skills are up to the challenge just yet.
Cheers
Darren
Actually it wasn't London bridge I was thinking of (doh!), it was Tower bridge and even that doesn't lift in the manner I was thinking of. A single span lift bridge was what I had in mind operating like this
http://en.wikipedia.org/wiki/Vertical-lift_bridge and strangely enough there is one in Tasmania
http://en.wikipedia.org/wiki/File:Bridgewater_Causeway_Crop.jpg
What do you think, would certainly be a stunning centerpiece (literally)if you could pull it off.