When to expect this? If memory serves mine came in at between 9 and 11 months, but so long since I raised B.C bitch can't be certain. Have "lent" relevant books to various people - why do we do this? - so would be grateful for consensus. I believe times can vary a lot so want to be prepared for earliest possible as she exercises a lot with my dog-walker's entire male, wouldn't want to upset the lad!

Any time from around 11 months to 15 months is usual but can be as long as 18months in my experience.

Any time from 6 months onwards.

Would agree with JG on the whole although I have had one that had her first season at 5 months old and then contiuned 5 monthly.

6 months upwards.  Opi had her first at 8 months, River had hers at 14 (both crossbreeds) so there is huge variation - I've heard of 18 months and older although it's less common.  A friend's bitch was 7 months (crossbreed again).

It can vary with lines within breeds from what I've heard as well, could you find out from the breeder an idea of average for the line?

My BC had her first at 10 months

gwen has just come in,aged ten months,but ive had one at thirteen months,

My GSD has just had her first season at 8 months all the other GSDs i have had have been over a year old so i was quite surprised by this one, we managed ok

Tends to run in the female line so ask the breeder when Mum and other female relatives came in for first time.

Many thanks to you all - will follow advice re breeder; I knew it varied a lot but never thought it could be as young as 5 months.
She's 7 months and a bit "clingy" the last few days so I'll be on watch for the signs!