From what i hear in rumours etc Home to Duty was requested by the unions with tongue in cheek not thinking we would get it. We did.
Not all units currently get Home to Duty Payments - Luton Tower for one I think
Management can give 6 months notice to withdraw Home to Duty Allowance and we would receive no payment.
To me the buy out on offer seems a very good deal - rather get almost three years of payments as a lump sum than nothing at all