It is possible for RAF rotary pilots to serve with the AAC on attachment. An RAF mate flew Lynx with 1 Regt while I was there in the early 90's. I don't know what the options for a secondment are like now as both the AAC and RAF are facing pilot shortages.
Joining the AAC will offer the chance to get down and dirty. As an NCO pilot you have to do a min 5 years in a ground support role and reach the rank of Cpl. If successful at OASC you have to sign an option to re-engage for a min 5 years on completion of the flying course. If you are unsuccessful you would be expected to see out the remainder of your initial engagement.
As you would deploy out into the field the Grnd Supp Flt of each sqn would be expected to recce forward operating areas and patrol the area and provide the security of the FOA. As a jnr officer you would be expected to take on a role developing their field skills and ytou would spend a proportion of your time doing the inf skills, flying, and admin/2nd duties. However, if as an officer you want a long term flying career then perhaps the AAC is not the option for you.