"One of the primary concepts encapsulated in limited liability exists to ring fence the debts of a company. If it didn't, then you could go straight after the directors and their personal assets."
Directors are not held harmless for illegal activities - and knowingly engaging in illegal activities is sufficient grounds for "piercing the company veil" to hold all officers personally liable.
The ICO _could_ get their money if they're willing to go to court and get a declaratory judgement, however they can't be arsed - all they care about is issuing press releases about "XYZ fine issued, woo woo"