If memory serves, all but XR809 (the RB211 test bed) of the C MK1s were converted at Bournemouth into tankers, so XV104 would have certainly flown after '88.
Whilst at Bournemouth, quite a few had major corrosion repairs carried out (the forward keel skins were replaced).
I'm fairly confident that the additional refurbishments that were carried out during the conversions allowed the aircraft to have a longer period in service than they otherwise might have.