What other requirements do you have? Like for contract length, phone, etc.?
You've got the usual players offering budget prices for 80/20, such as Sky (£25/m), NowTV (£24/m) and TalkTalk (£23/m) with varying options and contract lengths. BT just misses the mark at £31.99/m, but would work out cheaper if there is cashback and because "3 months" free. I have no idea how these providers are compared to the old Plusnet.
£30/m is going to be a barrier for anything "premium" at 80/20, if you were interested in such options - the likes of Zen, IDNet, and AAISP are £34.99, £38, and £45 likewise when taking into account your 80/20 requirement. Don't forget there is also Pulse8 at £33/m, with zero cost for fibre to fibre migration - they are a decent middle ground between budget and premium in my opinion if you like a 1 month contract.
Talking of AAISP, when I was a subscriber with FTTC, they did have the option to set the rate at their end - this helped with bufferbloat a bit when downloading if I recall correctly. This was alongside their monitoring that could at least text and email you when your connection goes offline. Nice stuff, but wasn't too helpful for me. Pretty sure there were some other features, but it's been a while.
I'm currently with Zen, and there isn't much to tinker with. You can see your usage, line data, and you can also setup a reverse DNS. Not much else with it comes to technical stuff.
In reference to the activation costs for Zen, those should still be applicable even for a migration.