Can you render over larch cladding?

All cladding would need to be removed , if there are battens underneath the cladding then you would need the larch clashing removed then cement board fixing to the battens and then it would need to be meshed and rendered, I would not recommend rendering over the larch

Absolutely not, the cladding needs to be removed. A cement board needs to be used with staggered joints and taking into account expansion areas around window's. An adhesive render with an alkaline resistant mesh used in the top 5mm of the render. A silicone coloured render then applied over the finished render. You could also have an insulated render system on top of the cement board if that part of the house is cold or damp.

Personally I'd strip the cladding (as it could rott underneath) and sort the wall out depending on the damage afterwards

Remove all cladding.battens .if original walls are sand cement.remove and go back to the brick.stone or cob.then rerender using a lime scatter for key .scratch in lime.float coat in lime.this will then breath for another 100 years.i don't know why it has been clad.a membrain on walls is rare.unless in a cellar.i would tank and lime render a cellar.