Screen sizes/anti-reflective screen protectors question

Hi all.

I have a Road Angel Navigator and am looking for a screen protector that
will also have anti-reflective properties ( a matt finish) when I use the
unit for hiking. There are a few available for TomTom etc but what I need to
know from you guys is:

The make and model of your satnav
Exact screen dimensions width and height

So I can decide which one to buy that will fit mine (No-one seems to specify
the Road Angel).

As a guide my unit has a 3.5" screen that is 71mm x 53mm (exactly) between
the plastic 'frame'.

Similarly I am also looking for same for my in car medion MD96800 which has
a very shiny screen and is exactly 72mm x 55mm.

I have never tried these, so also would like to know from anyone who has -
are they effective in improving readability in bright conditions?

Finally, does anyone know who might supply these filters at a reasonable
price. I was recently quoted £3.99 (very reasonable) but postage costs £3.99
(extortionate for a thin piece of film!) - total nearly £8!! NO WAY.