Understood. To be honest I don't think it's of any use for you either way. Your monthly plan costs you 110gbp a year and it's another 100gbp fee to actually invoke the insurance and get the replacement iPhone. That's incredibly expensive for insuring a 2 year old used device. You can buy a used one in good condition with seller warranty for under 400gbp and from a private seller for under 350gbp and the value keeps falling month after month.
I'd cancel AC+ and put that money towards an iPhone replacement fund. And by all means do get AC+ with theft and loss coverage on a brand new model where a replacement would cost 1000gbp and more.