Totally agree with Shaun. The price to charge for a service, is what the market will pay, but if you're in a competetive market, you need to give your prospect a reason to use you, rather than x,y or z.
Find out what they want, their expectations, against the condition of the carpet.
The size you're quoting, is a very small room and should take no more than 40 - 45 minutes, including, setting up and repacking, so, in my world, it would be a " minimum charge" job, of £35, which is my target, hourly rate.
Even the Franchised people, with their high overheads, would not charge more than £70 - £80 for a small room.
Angie