A good rep yes. but £55 for 160/30 (£10 more than A&A) seems a bit steep to me!
The 1TB quota that you get included for the £45 you are comparing on A&A is a significant limitation, with it costing that extra tenner to go up to 10TB (no unlimited option on AAISP) - which would be the fairer comparison. I think for many the 1TB quota option doesn't really cover their usage (it didn't for me, a house with 3 people streaming but no significant downloads), and adds to anxiety over the service. One of the nice things with FTTP is it "just works" it seems, and so having to watch over an aspect of usage is an annoyance.
It seems Unchained have recently increased their new customer retail pricing, though I think it looks competitive still compared to AAISP. My contract (from Sept 2023) is currently at the £56 inc VAT level for 1000/115 uncapped.
There doesn't seem to be any mention of a process for tariff increases in the terms and conditions, so I suppose I'll see what happens when September rolls around.