I researched this about a year ago but wondered if anyone had bought the various components needed and installed themselves and could recommend a good supply option? thanks

I’m following this too for a garage roof!

Not personally but designed and had it built where the original architect had included it.,

missing out the package deal people and saving a lot.

So yes, you can buy the bits and do it..

Is this a requirement or your own choice?

Yes planning requirement but it should also be a good feature

4 hours ago, markharro said:

should also be a good feature

Bear in mind maintenance. Plants grow and die so may need maintenance and you need safe access.

The membrane has to be roof resistant. Some of these are not uv resistant so perhaps a joint is required.

Consider laying a grid to contain the plants.

This is all very heavy (wet earth) and the roof needs to be designed for it.