Welcome to the forum!
I have three bonded lines from AA, have been with them for over eleven years. Triple speed in both directions. The £200 per month figure sounds like Office::1 perhaps? I don’t use that, I have three Soho::1 accounts and it’s rather cheaper than that for my three lines never mind two. It’s difficult for me to tell you exactly how much my three lines costs me because my bill contains other services such as 4G SIMs, email, DNS, domain name renewals x many etc. I pay line rental times three to AA as well.
I have a Firebrick FB2900 which handles the bonding at my end, AA’s Firebricks do the same at their end. If all lines fail it switches to 3G.
AA gave me a free IPv4 /26 and of course I have IPv6 too. No NAT
! Just ask for the IPv4 space you need.
I recently did a post for someone else about the good things I find about AA, just need a bit of help finding it.