Hi, I thought I'd drop by with an update. I'm unable to edit the original post.
Earlier today I had a phone call from Lightning Fibre finally giving me good news, my street is live. The order process was easy, they had most of my details from the 'register my interest' form ages ago. The only information they needed was for setting up a direct debit, of course. I've been given a fantastic deal on their gigabit package (making the total price per month less than £30/mo compared to the current £44/mo), especially given the lengthy wait and how long I've been out of contract with Cerberus paying a rather high price each month.
I asked how the connection is established, e.g. PPPoE or IPoE. While the person on the phone wasn't certain, they believed like me that it's IPoE. No authentication details are given for the connection, at least I've not seen any on their members portal and had no such details via email. I was also told that they might be re-evaluating their pricing for a static IP address (at £10/mo), as they've observed that it's a fair bit higher than many other ISP's via Openreach's network. At the moment I've not opted for a static IP address, I may not need it even though I use a GRE tunnel (Mikrotik supports using a subdomain/domain name for the 'remote address' on a GRE tunnel so I can likely use DDNS).
They are aware that I will want to use my own router instead of theirs which is fine, they also suggested to make sure that the engineers are aware of this on the day of installation.
By the middle of next month, or sooner if there's an earlier installation slot that becomes available, it should be installed. Once it's done then I can sort out cancelling my FTTP service with Cerberus Networks.