Hi Paul, we moved premises & set up an ATL 2 years ago. We basically sent in the application before we had even signed up the lease or purchased any equipment. Our local VOSA guy came out and had a look & meassure up. They then give you an approval in principal, so although you may have to do a bit of paperwork beforehand, you don't have to carry out any work (or spend any money) until you're sure you'll get approval.
Hope this helps, Ian.
p.s. the quotes we had for equipment varied by a huge amount. In the end we went for a Ranger test lane with a scissor lift and a Bosch Gas annalyser/smoke meter, both have been trouble free.