my great-grandparents came to the UK from Poland in 1908
They weren't. Poland didn't exist at that time.
Do you know in which port they arrived when they emigrated to the UK? Try to find an archive with ship manifests and search their data. If you're lucky, you will find an entry which you can then trace back to the port of departure, which - I'm pretty sure - will be in Germany (either Bremen or Hamburg). There are several emigration museums in Germany which might hold the genealogical data you are looking for.
Usually, you will find the last residence and the age of the passenger, as well as the names of the family members accompanying him/her on the manifest. Once you know the names, follow the link to the last known residence, and then check the LDS database for the relevant church books.
Looks as if your ancestors anglicized their family name a little. You might want to check different spellings.