Any tips on how to remove a c402, I want to replace like for like to freshen things up.

Basically they are a screw down to floor and attach plumbing, check U Tube for how to videos such as www.youtube.com/watch

Thanks, there is a lot on pumps and cassettes but not on the install.

Thanks, yes saw that one. No good still anyway. Ok toilet is out. Found 4 screws behind lid after you remove lid. Pull edge stripping off, give whole unit an upwards pull with vigour, unit is mounted to back wall on brackets, unit slides down vertically onto them. Disconnect wiring, now our shower toilet is combined so I had to remove some of the door frame to get unit out of the room as the unit is a tight fit against the walls. Now to clean the room and remove all the old sealer and make smell nice again before reassembly.

Good to hear, the C402 is an easy fix as it is self-contained - Time and patience overcomes most obstacles.

Howdy, I just noticed this post. I was thinking of doing the same sort of thing, but it was looking a bit of a major job with the external door etc. From what I gather here, seems like the main toilet unit lifts out from inside the van, and the external door frame and door etc. Remains in place ? Would that be correct ?

You are correct Rob - There may be a coating of Silicon RTV between the wall and C402 body.

See Thetford images www.bing.com/images/search you will note it is a self-contained unit,

Thanks Possum for the links.
There are parts shown in the videos that have no mention of them in the "booklet" supplied or how to get them out.