After I posted my initial query, I read up on several posts relating to similar types of queries and decided that I should try aim for a longer nap on his own in his cot. Whilst reading some of the other posts I felt that my guy is probably over stimulated, not necessarily over tired. He is very aware, loves looking around and laughing, so he "does" quite a lot in his activity time and I wanted to see if he would benefit from a longer wind down.
So this morning, he had his bottlle at 7am (but I first heard him at 6:40am) took him downstairs to his bouncer, but I removed one of the 3 hanging toys immediately. He sat their happily enjoying himself, gradually I removed all the toys to let him sit more quietly as part of his wind down. By 8:10 am he was looking tired, not yawning but definitely getting there. Nappy change and back up to his room, for some more wind down, couple of songs, then came the yawns and he was asleep by 8:20am, it's now after 10am, and he's still asleep. His next activity time is usually more active as he spends time on his tummy and playgym, but I'm gonig to increase his wind down time and see how that goes.