F
Flintstone
I can't see what is wrong with receiving an enquiry by text like this. You can answer it in your own time when you have thought about your own time schedules etc. and whether you are interested in quoting for it. It is far better than the mobile phone ringing when you have just mixed a bucket of fast set on a hot day!
I used to put a line in my quotes something like "As part of this work I will be pleased to calculate the quantities of tiles that you require when you have chosen your tiles." I hated it when I had worked out quantities of all the different types of field and border tiles for free (for another tiler to then fix) so I made it clear it was part of the paid work.
I always measure up when I look At a job as it helps me to work out my price.