Completely agree with CommanderB's post above.

Everything should be fine - I have seen multiple huge bags brought on my recent flights. BUT - rule are rules, and if they have 'one of those days', where they enforce the regulations to the letter - you must have a Plan B to avoid valuable items, that you don't want to lose sight / control of, being checked.

I booked some more flights this morning, and attached to the confirmation email was a PDF explaining their rules in full. That may mean they intend to be more strict in future - other airlines already use excess baggage as a cash cow.

I have attached the PDF for information of all.

Nick