Underhill itself isnt too bad,
The key issues are to do with access and the councils refusal to allow improvements. We used to lease the cricket pitch behind the south stand from the council and we had a right of access behind the East Terrace to enable vehicles access to the southern end of the ground.
Problem started when the council asked for a large sum of money to allow us to continue using the access road and to renew the lease on the cricket pitch.
Without this access it no longer complies with football league requirements so the writing was on the wall.
The other factor for moving is the cost of maintaining an old ground was a burden. Particularly as the main stand was built as a time when asbestos was regularly used as a building material and so extra care has to be taken.