I really like it and i wanted to experiment with playing some chords over the top and am hoping that if i can find out the key i could perhaps put some of my theory to work....

I agree, the key of B. When I strum a B chord over it it seems to fit right in. The relative minor would be Gm.I don't think it's in D
The little piano riff is A# A# G# F# D# (rpt), which is more like the key of B.
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