As a rule of thumb I used to charge....
£25 per meter flat rate always PLUS materials ALWAYS using BAL and NEVER taking rubish.
I used to tough customers extra work and get extra cash out of those where possible with 'tanking talks' and photo's of before afters in bas moudly old showers that i'd done. And i'd dot and dab and even do studied walls (both really easy to do and can gain you a week job out of a 3 day job - always nice for pushing your book dates weeks ahead of you giving you more guaranteed income).
£35 per meter stone - earn a bit on sealers and treatments and preps where possible too.
£40 for Diamond floor or walls. £45 for Octagon and 'dot' affair's.
Always would include re-fisning old bathroom cabinets or curtain poles or loo role holder and even some new.
Always would clean up daily no matter how nackard I was.
Always used to insist I stood with the customer and waffled with them for at least half hour no matter how much of a rush I was in at the quote stage and used to tell them all about their job and other jobs i'd done similar where the 'feel, felt, found' tecnique i've mentioned on here always came into action.
Checkout this price list that OUT OF DATE NOW TOO....
http://www.tilersforums.com/check-my-pricing/2221-pricing-job-complete-list.html