Can't post to Isle of Man by Royal Mail

Shipstation's integration with Royal Mail does not recognise Isle of Man as a UK domestic service. It only offers international services.

According to Royal Mail, IoM is available for domestic services and not subject to customs documentation. 

https://personal.help.royalmail.com/app/answers/detail/a_id/98/~/help-sending-mail-to-the-channel-islands-and-isle-of-man

My bodge workaround is to change the country to UK, but this is incorrect and time consuming to have to intervene manually. Please can we have a fix for this issue?

Thanks.