Flugpants,
I agree with the Radalt on this; in 1998 I was part of an 18 Sqn Chinook crew which carried out a request from Bristows to carry a damaged SAR S61 from N of Ullapool back to Dyce for repair. Many other tasks in support of non-military agencies have been carried out, eg replacement of VOR destroyed by strong winds near Unst. Such tasks will be extremely costly - the beancounters positively drool over such opportunities, but there may be a case for convincing the Sqns that the training value offered will justify the unit using its own costed trg hours.
Mind you, I've been away from the UK system for nearly 3 years so this opinion may no longer be an accurate reflection of current policy.