I thought the first part of the first series was pretty weak, but it picked up a lot in later ones. The change of writers did it no favours though.
I loved the episode where the leisure centre was under siege by Roman reenacters because Brittas was holding the Centurion's son captive. It ended, as I remember, with the Romans catapulting the engine block of a Morris Marina through the Brittas' window, which had me helpless with laughter.