HiI think £7.50 is just right for front only window sills frames.My mum friend got a windows cleaner who must be about 60 year old who charge £6 for a 3 bedroom house.That far to cheap for me.My mum friend ask me what my quote are and I said nothing less than £15.I thought she was going to pass out but I point out it would take me 20 min drive to clean 1 house.There was no way I am driving for 20 min to clean her window for £6