Hyperoptic Website: Register Interest form broken for 3+ weeks

I've been trying to register my interest in Hyperoptic after their postcode checker told me:

“Get ready for full fibre - we're arriving soon!”

It then gives me the option to Register now, but every time I submit my details I get:

“There was a problem. An error has occurred. Please contact our Customer Service 0333 332 1111.”

I first tried registering about 3 weeks ago, and the form kept failing. I left it for a while hoping it was just a temporary issue and would be fixed.

After it was still failing a week later, I called Hyperoptic 2 weeks ago.

The first person I spoke to actually tested the registration himself and got exactly the same error. He then passed me through to support, who also tested it and had the same issue.

The support person said she would pass the issue on to the relevant team and told me to keep checking the website.

It's now 3 weeks since I first tried and 2 weeks since that call, and the registration form is still giving exactly the same error.

Has anyone else had this issue, or know of another way to register interest manually? I'd quite like to make sure my address is actually registered for the rollout rather than just repeatedly checking a broken form.

Pretty disappointing, to be honest. It does make me wonder how good their service actually is if they can't get something as basic as this fixed after 2+ weeks.