Hi everyone,
Thanks for all of the helpful replies. It has been a stressful few days and the comments have been a great help.
Lots of phone calls going back and forth but have finally got access using a surveyor. After he talked with EA he agreed about how difficult they are to deal with. At least it's not just me!
Had a long chat with the missus yesterday and despite the difficulty we've had, assuming the survey doesn't indicate anything wrong, we'll proceed. We've a good few reasons really, and as difficult as the EA and vendor are to deal with it's not quite enough to pull out. Although I've been on the verge of doing so several times over the past couple of days.
It's a measured risk and I'm definitely not happy about it but when we weighed up our options, going back to looking for another house isn't one we want to go with. This isn't an emotional attachment to the house - it's just logistics around her work and mine, and we've a baby on the way. It took us ages to find a house that suited us as I'm out of the country for work a lot and she works shift work in a different county at the moment. Going back to the market, running the risk of finding another house needing probate, or the owners in a chain etc.... when we weighed it up it made more sense to stay the course.
I just hope there's nothing wrong in the survey. I've a BEng in Structural Engineering, although I never worked as an engineer. I'll never live it down if I missed something!