Any recommends for a good all round product for keeping the engine plastics clean and shiny. The state of our lanes at the moment leaves crap all over the engine and pipework.

Hi

Autoglym bumper gel is brilliant but only really for shining not cleaning.!  405 AB exec seats Baltic and Cirrus
93 RR Classic efi

Remember it's easier to get forgiveness than permission!

Gone in order:
4.4 TDV8 SE - gone to a good home
93 Classic hard dash Plymouth Blue
03 L322 Oslo Blue
2000 Disco TD5 ES Epsom Green
98 P38 Rioja Red
89 Classic Cairngorm Brown

I tend to give it a spray with some Gunk or similar every now and then, leave it for a few minutes then just give it a little rinse off with some clean water (keep away from the battery and electrics) Once it’s all dry a spray over with a can of WD40 or similar then a wipe with a rag tends to keep it looking good. Certainly don’t drown it with water and Keep the WD40 away from the belts.
I’ve applied this method for years and every vehicle I’ve sold the new owners have always commented on the cleanliness of the engine bays.