water filter

I have just bought a Symphony and am trying to work my way through how everything works using various manuals but some things don't seem to be exactly how my van is.
Re the water system the manual refers to a filter next to the pump which is accessible via a hatch under the offside seat cushion, there is a hatch but this provides access to the water heater? There doesn't seem to be any way of accessing the pump to see if there is after all a filter. Unless I am doing something daft.
Also does anyone have a good method of stopping window rubbers from sticking to the window when laid up over the winter? I got mine part but only with a lot of care.
Thanks in advance. It is all pretty daunting at the moment. I expect further requests for help will follow.
Sorry if I haven't done this post correctly. This is also my first forum experience as well.

I've just replied to the same question re water filter to another poster, our Symphony never had one despite the handbook telling you to replace it. The water pump by the way is under the false floor in the bottom cupboard under the cooker. Vaseline was what I put a smear of on window rubbers when we had a caravan.

Re window rubbers, I was advised to use talcum powder.

IIRC the water pump fitted to older A-S models (and possibly newer models, but I've never owned one of them) is typically a Shurflo Trailking, and every example I've seen has a small mesh filter in a small plastic housing attached at the inlet side of the pump. None of mine have ever needed any attention at all.