Personally I’d pay 30mins on a meter, a lot cheaper than a fine, and the wardens go round on scooters a lot so can cover more roads right up to time limits
Just realised you didn’t say if your biking or car. Lots of free bike parking, but if in car don’t forget congestion charge depending on your route in.
This one’s very good - never full, and it’s free. Go through the barrier and keep heading down. I think the majority of the 60-odd motorcycle spaces are on the sixth floor down. But not very close to Park Lane, unfortunately.