The average price for a tiller (outside of London areas) is around ?35.00 per square meter. However one can usually find much better deals than this if one gets 3 quotes which is always recommended from tillers.
2 Additional Answers
Tilers charge around £20 per hour. Usually, they are registered with a trade body or in an approved listing like Check a Trade. Sometimes, the local council also has a list of approved contractors. You will have to supply the materials on top of that price too.
Depending on the city or town in the UK, tilers can charge anything from 20 to 40