Folks,
Thanks for the advice on this.
In the end I brought my larger bag with my Camera bag and there were no problems. The crew at the gate didn't look twice.
In fact a gentleman in front of me brought on his guitar in a soft case without a glance!
Having said that, the aircraft was probably only about 3/4 full..
As an aside, finally heard the A320 'dog barking' noise that I have seen mentioned on several posts on pprune. Must agree, dog barking is a very apt description!