[BAracer]

That's really helpful, thank you. I now have a better idea of scale.

No access to top edge and right hand edge of layout. I was imagining I would stand by the bottom left hand corner of the right hand leg. 

Latest news is that if a certain eBay buy and sell combination happens, I will be able to get two further tables to extend the left hand leg down the page by a further 2400 x 800, so there's my straight!