Thanks for the clarification. I'm afraid that the ex-gratia is just that; i.e. they don't have to pay it. While it appears unfair, once they are doing this for all in the same boat as yourself, it is actually fair. They could have changed the terms to something like '4 weeks per year to max 1 year's salary' or the likes which they could have fixed to pay out the same. Given that they are paying 10 years, and not 9, it is not impacted by TUPE. In reality you are getting weeks per year for 10 years of your service which is quite good.