Hi Graham,
The capacitor in question is C27 on the ERT sheet you downloaded. It sits across the Live and Neutral wires after the mains switch. If you do replace it, not necessary at this time, the replacement should be an X2 type capacitor. As Chris mentioned early on, it's listed on the ERT sheet as an electrolytic but it is not.
I think I spot the end of C27 that blew off
Andrew