There's another way to penny-pinch yourself a screen protector for the n810

The one it comes with has two stickers on it, but with a bit of care you can remove them leaving the existing already bubble-free correctly sized film in place.

As I've had to return one unit, I had a chance to get it wrong the first time and refine the technique the first time I pulled it off, stuck it down on another surface, peeled off the silver tab (this came off fine leaving no residue) and the sticker, leaving behind the silver anti-tamper diamonds. These I scrubbed off using some tissue paper with a bit of white spirit on it.

Unfortunately after sticking the film back on, I found that doing it that way had left enough dust/oil/fluff on the sticky side that it ruined the look of the screen.

Second time around I left it all stuck on and this time, not having any white spirit to hand, I sprayed a bit of anti-static foam cleaner on it and gently wiped away the silver stuff/glue with a cloth.

Worked a treat - free screen protector, touchscreen working just fine/only a little less responsive than the previous one where I ended up taking it off entirely after the dust issue.