The chances of them being given leave to appeal a unanimous decision written by the Master of the Rolls are slim.
The DBS check is interesting because it's the specifics of what they're objecting to. Cofty's right, thousands of other organisations do this already. I believe it would even be free for both elders and the WBTS to do this as they are unpaid. But it has significant consequences as it is a criminal offence not to report someone who should be on that list, and it's a criminal offence for both person and those who employ/appoint him if such a person is placed in a role which they shouldn't be in. This is really significant. They'll kick and scream as loudly and for as long as they can over this. It takes accountability all the way to those who approve an elder's appointment. And has the potential to expose a lot of things the WBTS would rather congregations not know about.