Thanks for the thought. No remote on a DX. I'd like to think you are right, but I'm not convinced. Same key operates the passenger door as perfectly. When it opens the driver it works smooth as. The key doesn't look especially worn. Car has only done 170,000 kms, mainly country/outback driving. The pattern seems to fit with what Wizard said. I'll give it a squirt of graphite, but I'm not holding my breath on it being the solution. I'll also try my spare key which is as new.