I think the easiest way is to guess those entries from the current province.csv for AGCEEP 1.51. Often it will be correct, certainly so for climate. Just keep in mind that all "coastal" equals port and a province at the coast can be "inland" i.e. not having a port but be adjecent to the sea.
Not used much for British islands, that had several ports, only Leinster and Lincoln didn't have a port. Just guess away! For example, all of 295, 298 and 301 should probably not be "coastal".
I don't know if Lancaster and Carlisle were important harbours, but someone will probably come here and tell you. 295 does indeed seem to lack a big harbour.