Tonga SG1217a 1993 20s on 4s Lionfish on OHMS envelope VERT RARE

1993 20s on 4s Lionfish on OHMS envelope used from Vavau to Nukualofa two CDSs with indistinct (inverted) date.  Circular double-ring TONGA GOVERNMENT/ INLAND REVENUE cachet in violet on front (manuscript date 28/6/94) and addressed to the Inland Revenue Dept.  Backflap with a tear which just extends to the front of the envelope.  A very rare cover with what (despite the a number) is a basic Tongan stamp.   Surcharged locally on Tonga to cover a postal shortage and there was no philatelic distribution. SG 1217a unpriced used (Cat 400 pounds mint)