FM 10416 air filters plus other bits required

I'm sure that this has been covered before but does anyone know of a sensibly priced supplier of FM 10416 air filters for my 1978 400 (carbed) - Eurospares part number is 100253

I want to replace both filters and also the gaskets between the trumpets and airbox and airbox to carbs. I know the quantities and have Eurospares part numbers for these if anyone thinks they can help.

Last but not least the oil pressure switch located next to the oil filters is leaking through the top by the electrical contact so I need a replacement - Eurospares number 110664

If anyone has new spares of these parts knocking around that they want to sell please let me know. I'd take a used oil pressure switch if it was ok.

Thanks,

Russ