Just to further highlight these options, here is a bit more information taken from both the VW and SEAT map portals.
UK coverage is only available on the following options:
FULL EUROPE -
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU-AS_2310_V20.7z - 32GB card
WESTERN EUROPE + UK -
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU1_2310_V20.7z - 16GB card. Coverage: Andorra, Belgium, France, Gibraltar, Iceland, Ireland, Luxembourg, Monaco, Netherlands, Portugal, Spain, United Kingdom
SOUTHERN CENTRAL EUROPE + UK -
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU-DL2_2310_V20.7z - 16GB card. Coverage: Andorra, Belgium, Germany, France, Ireland, Iceland, Italy, Liechtenstein, Luxembourg, Malta, Monaco, Netherlands, Austria, San Marino, Switzerland, Vatican City, United Kingdom
NORTHERN CENTRAL EUROPE + UK + Scandinavia -
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU-DL3_2310_V20.7z - 16 GB card. Coverage: Andorra, Belgium, Germany, Denmark, Finland, France, Ireland, Iceland, Luxembourg, Monaco, Netherlands, Norway, Sweden, United Kingdom
POLISH coverage on available on:
FULL EUROPE -
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU-AS_2310_V20.7z - 32 GB card
EASTERN EUROPE 1
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU3_2310_V20.7z- 32 GB card
EASTERN EUROPE 2
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU-DL1_2310_V20.7z - 16 GB card - same as Eastern Europe 1 + Andorra, France and Benelux
FULL EASTERN EUROPE -
https://navigation-maps.volkswagen.com/vw-maps/DiscoverMedia2_EU-DL4_2310_V20.7z - 16GB card
The ONLY map available with both UK and Polish coverage is the FULL Europe link above
Big thanks to both
@Tell and
@cairus for the info they have provided