Roofing quotes start with you on a ladder trying to read the pitch by eye, then guessing tile count, scaffolding hire and battens. Half the time the scaffold quote isn't back when you need to send the price, so you guess that too. Then you find out the EPDM was actually a re-felt and you've underquoted by a grand.
Sketch the pitches, pick tile vs slate vs EPDM, tell Hint how high you need to scaffold. It prices materials and labour against live UK rates, breaks scaffold out as a separate line you can forward to your scaffolder, and surfaces the questions that bite (battens, felt grade, ridge tile).
Free to start. Open it and have a go — pay only when it's pulling its weight.