Volcanic Ash at EGHH

[pulse1]

The EGHH METAR this morning is:

EGHH 200750Z 26016KT 9999 FEW020 SCT046 11/09 Q0989 REVA

I cannot see any other airport reporting volcanic ash so it appears to be very local.

Where is it coming from and why so local?
What action should pilots take before approaching EGHH?

[Farmer 1]

Probably John Reid blowing his top.

Actually it could be birch pollen from Denmark(?) I doubt there is a METAR code for that.