I have just taken Willow - 14 week lab - in the back field. She's having 15 minute walks now and she normally just trots round behind me off the lead. ( Yes I am taking her out on lead walks on the road too!!) We bumped into a 9 month old lab and they had an absolute whale of a time rolling over each other and jumping at each others ears - I am sure you can imagine! Anyway I was a bit worried that it was too much for Willow's bones so after 10 mins I suggested to the lady that we split up in case it was too much for Willow and the other lady agreed. However it set me wondering what the advice is on this. After all if Willow wasn t an 'only dog' she'd probably spend hours playing and rolling round with other pooches.
What's are your thoughts on this?

I always advise..... do not let your pups play with dogs of unequal weight or size. too risky.

If they're reasonably well matched I like to see them play like this and it's so good for them to have a pal they can roll about in the dirt with!  I just do as you did and call a halt after a short while.  Both of my dogs would (and still will) play like this when their sisters visit and I just exercise rules about when, where and for how long they are allowed to play.  Where they play has a significant impact on the safety aspect and hard slippery floors are more dangerous, grass is generally good although they get filthy in this weather, and indoors can be annoying for us and the other dogs, particularly as they manage to move rugs and furniture in the process!!

Treat it as just another training session, she learns how to play with this new dog, but also learns that it stops when you decide it should.

It's true what you say about treating it as a training session. I was very pleased with Willow that she came with me when I called her away.
Useful to bear in mind the 'well matched' idea.
Thanks

I would suggest that you ask the other person to put their dog on the lead and to restrain it gently if you see that the play is getting uneven.  You can help 'equalise' the play by holding the larger dog off somewhat.  It's something I often do at class when supervising puppy play.