There is no evidence that he was working for western intelligence. If he was affiliated with Russian intelligence...how better to be productive than to "buddy up" with numerous western diplomats. If he was a western intel asset, what was he doing hanging out in London? How was he helping the west? He had a lot of contacts. He didn't even have to be an asset for either side. He may have been told by someone that the Russians had dirt and he passed it on.