If you go to Afghanistan you won't do very much ceremonial at all.
If you go to Woolwich you will do quite a bit.
If you go to Aldershot you will do a bit, but not too much.
I'm not being flippant, it just depends where you are and what your company is doing. The Battalion may be doing a heavy stint of Public Duties, your Company may end up adventure training. It's not as clear cut as how much / how often. Lots of factors dictate the answer.
Ceremonial and Operational roles are completely interchangeable. This is know as the "Dual Role Concept".
For instance, Guardsmen from the 1st Battalion Coldstream Guards, who are preparing to deploy on Ops at Aldershot, have been tasked to provide a Guard of Honour at the Ministry of Defence, London, on Monday 30th for the arrival of the President of Mexico who is being hosted by the Queen.
This unique role has been in existence for the last 360 years.
You might find yourself posted to the Coldstream Guards ceremonial Company (Number 7 Company), who ae ther specifically to carry out ceremonial duties (although they do manage to escape them from time to time).