CDC and LHR revivals lounge question

We are flying back in to LHR from JFK in July and I'm working out the best way to get us back up to Manchester. I've got quite a few miles at the moment so am thinking I'll spend some on a CDC to take us to Milton Keynes then jump on a virgin train up from there (can get advance first class tickets for less than £50 for the two of us).
My question is about how the limo service works with revivals. We should be landing at 0925 on VS10, if I book a CDC will I have to set a time or does it get arranged on landing? It'd be nice to have breakfast and a treatment before driving to the station but if we prebook our train tickets, whether we have time would depend on lots of things (flight delays, immigration, luggage arrival, traffic on the M25...). Is there flexibility once we get to LHR to rearrange things?
My question is about how the limo service works with revivals. We should be landing at 0925 on VS10, if I book a CDC will I have to set a time or does it get arranged on landing? It'd be nice to have breakfast and a treatment before driving to the station but if we prebook our train tickets, whether we have time would depend on lots of things (flight delays, immigration, luggage arrival, traffic on the M25...). Is there flexibility once we get to LHR to rearrange things?