Portishead was disbanded for several reasons. Historically it had split from Clevedon congregation but over time attendances dropped and it was full of older people. A couple of younger families did move across from Clevedon but it's been one of the those old, parochial places for some time.
Clevedon and Portishead continued to share a hall in Clevedon, a old Victorian building which backed right onto a hillside. The building is listed which means you have to get lots of approvals to do anything to it. Of course, each year that goes by means it needs more maintenance work.
Clevedon and Portishead congregations have been looking for a new hall for years. The main problem has been that the Clevedon congregation wanted to keep the hall within Clevedon and not have to travel. All the sites that came up had planning problems because they were on a flood plain. During this time the Bethel were slowly taking more and more control of hall planning tasks and saying to the congregation they needed to look elsewhere.
At some point earlier this year the Bethel pulled rank. They sent the RBC (as was) round and surveyed the hall. They said that the hall was not really safe to use due to the risk of a rock fall and other maintenance issues. They sent Clevedon to Weston which already has 3 congregations meeting at a hall. Portishead were sent to another hall but then told that as of the new service year they would be disbanded. Portishead congregation members were sent to three congregations depending on where they lived.
Clevedon has basically been told to await the LDC's guidance on what will happen with the hall. They have been warned not to do anything themselves otherwise the LDC will drop them and they will be on their own. They cannot even verify with independent surveyors what the real state of their old hall is. On the one hand this has wound the locals up something chronic since going 10 mins down the road is a big PITA for them and they don't like being backed into a corner by Bethel. On the other hand the hall is a money pit and the high level argument for the way Bethel are spinning it makes sense, but one does get the impression that the LDC are taking advantage of a set of circumstances to get shot of a desirable building and get the cash without having to go to the trouble of building another hall. Of course, Clevedon & Portishead have been saving for years for a new hall and AFAIK all the cash they had on hand has already been scooped up by Bethel in the last funding round.