Undertrays and wash pump advice

Hi. Civic 5 door hatchback 2015 (9th gen) 1.6 diesel manual, 66k miles. Bit of advice please. I only do the brakes on this car as the garage does the rest, spring replacement, oil changes etc servicing to keep the service history going, it's a dear game these days looking after a car.

It's my wife's car so I don't drive it very often. I need to remove the mahoosive under tray to get to the underside of the engine to investigate an odd noise from the engine bay. The metal section is stuck fast, the fittings have rusted in place and it also appears to have been rivetted although they could be factory fitted, no clue. Anyhow I'm not sure it's going to go back on as many clips are damaged already or missing. Do many of you guys run without the front undertray ok? Got to be better for rust protecting too surely.. I'll also be looking at removing some of the rear under protection as is looks like it's gathering road rubbish, stones etc. I live very rural and our roads are a mess.

The other issue is the windscreen spray pump, it's not working. Is it a generic one or a Honda specific part please and is it accessed through the wheel arch liner or another access point please?

Thanks.