1. As you know, you have to put a pipe insert into any plastic pipe at a connection.
2. If you use Hep2O pipe, their standard inserts are fine.
3. If you use JG Speedfit pipe, they do two types of insert, "Superseal" (with added O rings like post #4 above) and plain. With compression fittings, the superseal don't give enough depth of insertion and the plain inserts should be used.
4. It is considered better to use copper olives, rather than brass ones, on the plastic end of a compression joint. It compresses better onto the softer plastic.
5. Do check the manufacturers instructions.
6. Note that there is a filter fitted inside the pipe at the final connection. I doubt this will fit a plastic pipe with an insert in it, although a Hep2O insert is more likely to suit. The supplied olive looks like a brass one.
7. There is a requirement to fit an isolation valve before the inlet. I would:
7a. Fit a decent full bore isolation valve like a Pegler (e.g. Screwfix 11085) with a short length of 15 mm copper pipe from valve to T30i inlet.
7b. Connect the plastic pipe into the isolation valve as described above.