Passenger side door locks not working

I've recently had issues with both passenger side door locks. The locks in general sound quite clunky and will intermittently stop working when locking the car. The diagnosis from multiple garages is that I need new door locks. Searching this forum, it seems to be a fairly common problem, although Skoda deny this.

I've already had someone check the wiring loom in the driver side door to make sure it isn't a wiring issue and I've also ensured the battery is fully charged as suggested by someone else on this forum.

I've priced the door locks with the Skoda dealership.
£228 each with a further £400-500 in labour due to the doors being riveted. Of course the dealership refuses to provide the part numbers for the locks for good measure.

I was provided with the following part numbers by a third party:

front left passenger door lock: OEN: 5TC 837 015
back left passenger door lock OEN: 5TA 839 015 H

Looking around online it looks like most aftermarket door locks available are only for left hand drive models.

Does anyone know where the locks can be sourced other than the dealership?

Also is anyone able to help me confirm the above part numbers are correct, as I'm currently unable to strip the door to find out.