As the title says - these options are greyed out, and I can't edit them.

Does anyone know why?

These options are not available when "series link" is used.

You have to decide whether you want to set every episode of a show every week or be able to adjust the start/stop times.

Naff really.

I fail to see why you cant do both like you can on Sky+
but its presumably a standard Freeview problem as my Humax and Pioneer Freeview+ recorders are the same

This isn't on a scheduled recording, this is on the 'Menu' screen, accessed using the 'Menu' button i.e. a global setting.

You can't change the option while the stb is recording