Sorry for not replying to all your useful comments.  I have been away and only just logged in again.  Thank you all for your comments much appreciated. !  think I may have solved the conundrum! I have full planning permission to build but, it came with 17 conditions attached!  one of which is that I could build but not occupy until some of the other condition have been fulfilled. I know some are unreasonable but I don't really want to fight it at the moment.   I have full permission to have a caravan/ mobile home sited until I have finished the builds and fulfilled all the conditions. Quite frankly, it going to take years to comply with them all so as long as I don't finish building everything I have permission, for I can continue to live in the mobile home.  So I am going to do the ground works for the annex and then place the mobile home, bigger than the annex, built to building regs placed on the site.