DWP letter dated June 2016 found cl eligible for award of standard rate mobility between July 2016 to June 2019 but stated in next paragraph “as you are in receipt of a pension from Poland the UK are (sic) not the competent state to pay you sickness benefit”. Next paragraph states “You’re not entitled to the daily living component from 27/7/16 because you’ve told us that you receive a pension from Poland. This means the UK isn’t responsible for paying sickness benefits to you”.
I don’t think PIP is a sickness benefit. If that’s right is it worth appealing?
The daily living component of PIP is a “sickness benefit” for the purposes of the EU co-ordination rules. (Perhaps it is not a sickness benefit in the sense that we might distinguish between a ‘sickness’ benefit such as ESA or UC LCWRA and a ‘disability’ benefit such as PIP or AA - but for EU law purposes, the definition is correct).
One of the co-ordination rules - see CPAG ch 70 or Benefits for Migrants for more - is that a state which pays you a pension is generally also the competent state for the purposes of deciding which state is to pay sickness benefits. Therefore if your client was getting a pension from Poland, it would be Poland which takes responsibility for paying whatever sickness benefits are due under its law and there would be no entitlement to PIP DL.
There’s also the question of how you would appeal against a decision made in 2016… although I suppose in theory you could request revision for official error and then appeal any refusal via PH & SM v SSWP  UKUT 404 (AAC).
Thank you very much for pointing me to the relevant information. I was completely ignorant but have now reviewed the matter in CPAG. The client is above retirement age and receives PC to top up the small Polish pension but as I read it she will not be eligible for AA on the same “competent state” ground?
Yes. In theory if she were to apply for AA, the DWP would then refer her case to the Polish authorities to consider whether she has any entitlement to equivalent Polish benefits, although this rarely works smoothly. It may be sensible for her to make her own enquiries with somebody who knows about the Polish benefits system.