Natal 1906 KEVII 1d Paying Late Fee

1906 Envelope from Durban (NO 4) to England franked KEVII 1d for postage and an additional KEVII 1d placed bottom left, tied with same datestamp as other, with notation at top "LATE FEE Pd". Sunderland arrival (NO 25) cds on reverse. Excellent example fulfilling the postal charges & requirements. Scarce.