Compass Omega Rear Partitions - Runners / Spares

Hello there welcome any help as my internet searches havent answered the problem / question

This year I bought a Compass Omega 505 and extremely happy with it. 

I have a niggly problem and being relatively new to this world welcome advice on spares / solution

In the Omega the rear area has a solid door ( 2 sections) that is on runners. Sadly when i bought the van i suspect one of the runners was on its last legs and has since lost its ' plastic' coating on the top wheel. this means the doors are moving and it grate when drawing across.

I have tried to source the spares cheaply but cant seem to locate the same thing ( i realise Compass is no longer around etc)

Its a l shaped bracket with holes for screwing into door with a wheel the seems to fit in a guide / rail

Do these spares exist cheaply?

Did other models have same thing?

Is there an alternative solution?

Is this a job i could do myself?

The door is now jumping out of the bottom rail ( a spring loaded button type)

Wlecome any thoughts or advice - suspect ill break it further unless sorted