UK Tax rebate cheque - any way to use it in Poland?

My Polish niece stayed with is a while back working in the uk . She returned over a year ago but has recently been sent a cheque for a tax rebate of £1200. We have forwarded the cheque to her but apparently she is struggling to cash or bank it. Does anyone have any suggestions as to the best way for her to do this ?

It is strange she can`t find appropriate info about it herself. Is she deprived of the access to the Net? There are a lot of sites with advice.

polishexpress.co.uk/jak-zrealizowac-w-polsce-czek-ze-wzrotem-podatku-z-wielkiej-brytanii