"Cockwomble - someone who engages in cottaging or gay dogging type activities in public places"

Not where I come from, never heard of it. Here's the definition I've always known and understood, and which is the reason for my use of the word to describe certain people....

"Cockwomble (noun) - A person, usually male, prone to making outrageously stupid statements and/or inappropriate behaviour while generally having a very high opinion of their own wisdom and importance.

synonyms: fuckwit, shit-for-brains"

Source - The Urban Dictionary (online)

From the definition Iains proposed, I'm guessing he must move in some very unsavoury circles. I guess we'll all have to take his word for it.