I had an email from a chap in VOSA a couple of months back regarding the removal of ABS & airbags. He said that "if it is obvious to the tester that it is a track / rally car they should not fail it for these items not being present" As for be obvious he said if it had harness, race seats, cage, rear seats removed etc then that should be sufficient.
He also said they were going to introduce the airbag changes in April / May and they would put out an updated guide then.
Trug