So i think 100 GBP a month is to much, i think they will end up with 1 month, 3 Month or 12 Month subscriptons from 50 to 100 GBP or something. Of course they need to get paid for the time they spend inventing the new cheese...but they also got a sence of business-logic as they know what kinda people theire customers are and what they would (or can) spend.
less is often more...
Let´s wait and see.