Utter tripe, I'm afraid (whether 16 years in recruitment or not).
If you are on 6 months notice, that sounds good to me. Few people walk away with 6 months salary when the worst happens.
A typical contract would be one months' notice, as you know, and an organisation making you redundant could 'get away' with as little as a few hundred pounds in statutory redundancy if it was that way inclined.
As a matter of interest, once you've been working there for 24 months continuously, you could anyway claim rights as if you were a non-rolling contract employee. This is why agency staff are so often removed from employment after 23 months continuous contract work - to avoid the employer falling into the employee rights issue.
Clearly Fr33 hasn't come across that either.