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  1. ... Rxh2
  2. Kxh2. Then Rd8+ is not possible ... Do you mean Rh8+?

Yes! My apologies I was looking at the Rook on d8 rather than where I wanted to move him

OK, then your variation is:

  1. ... Rxh2
  2. Kxh2 Rh8+
  3. Kg1. Enough for you to win? :)

Yes actually then the black Queen captures g3 and the pawn is pinned by black's Bishop

Indeed!
However @pompe72 was faster this time - check above. :)

wait this was wrong

The critical continuation is:

  1. ... Rxh2
  2. Kxh2. Can you win then?

My white player doesn't want the rook.

I would do it like this:

1.... - Rxh2
2Nh4 -- Rxh4
3gxh4 - Bh3
4Rg4+!- Nxg4
5Qxg4!- Bxg4
6Ne4 -- Rh8
8Kg2 -- Qh2

with f3 covered by the white bishop on g4

Black is convinced white doesn't just need to lose, the position merits punishment while white has a sense of humor about it.

If you want to win as black you must have a good answer against every white defense.

By the way, if white plays 2. Nh4 black can win much faster than in your variation ... :)