As a regular visitor myself to St Margarets Bay on the Kent coast, this has been a known issue for quite some time with 2G phones. It can also affect 3G phones if conditions are right. EE has now issued advice to turn off roaming while in the area of the village (or turn your phone off) to avoid being hit with an unexpected bill.
http://www.bbc.co.uk/news/uk-england-kent-21739029