Availability Checker: "capacity will be restored asap"

I'm in a situation where I currently have FTTC (with Plusnet) where I live. If things go well, I should be moving soon, but within the same exchange area. I know the current phone number of the property we will be moving into, so I ran a check on BT's checker. Got this:

https://i.imgur.com/roAj7uh.png

I checked this a few months ago and it was available, but checking just before Christmas gave me this capacity notice, albeit with an earlier date that has since been moving back every time we hit it (typical BT checker date issue...).

I do wonder if it's a case of simply adding more line cards, or whether a new cab is needed. roadworks.org isn't showing any upcoming telecoms work for that cab at all. Does anyone have any experience with waiting for this to be sorted, and if so how long can it take? As you can see the ADSL2+ speeds are pretty awful.

Could be a few weeks, could be a few months, that is the variation of experience.