Supporting aircraft at sea organically is difficult in this world of contractor support and just in time logisitics. You need to be able to front load critical spares into your RFA before the TG sails. What we discovered on Ark's last deployment was that the contract and aircraft fleet in the UK could not support having certain assets 'stuck' at sea in the RFA or in the hangar.
Interesting. Was that a MIOS or SKIOS issue? Or Harrier? Suggests that someone hadn't framed the contract (or the spares provision under the contract) to account for squadrons at sea. Not that we'll ever be able to have "one of everything just in case" again - but does highlight the importance of knowing how you're going to operate and thinking it through if you're going down the CLS path.