A few points here.

For confirmation, I am a cyclist.

Yes, the cyclist was in the wrong. No argument.

No, the make of the car is not important.

Yes, the barriers are obviously an entrance point to Grierson Road as well as clearly marked (on the other side of the barrier) as being a cycle path.

Yes, it is very frustrating that people parking their cars do so blocking these entrances. This situation is made worse with the "moo" bin having been moved to beside the barrier, and the constant dumping of rubbish bags on the other side.

No, I have never hit a car parked there but I've been tempted.

With reagrds to the roller blader, there are a couple who "blade" down Brockley Rise, one doing so in the middle of the road whilst wearing headphones.