An 1856 mixed franking cover sent from Hobart to England is to headline the Koichi Sato collection of Tasmania stamps at David Feldman in Geneva, Switzerland on June 27.

The Hobart to England cover is thought to be the only example to feature mixed franking of the Courier and Chalon Head issues

The lot is the only known cover to feature both the Chalon Head and Courier issues, making it exceptionally valuable. It carries an estimate in excess of $40,851.

The Courier issue was released in 1853 and is so named for the local newspaper whose publisher, H & C Best, was responsible for the printing.

The Chalon Head issue (named for the portrait of Victoria by painter Alfred Edward Chalon) came later, in 1855, and largely replaced the Courier version.

The cover features London and GPO (General Post Office) datestamps with all three stamps tied with "68" cancels. Feldman describes the lot as "a highly attractive and unique mixed issue cover" and "an important showpiece".

The Hobart to Campbell Town cover displays a strip of four Courier stamps with the guillotine guide present

Another cover sent from Hobart, Tasmania to Campbell Town in New South Wales is valued at $20,425.

It bears a strip of four 1d Courier stamps that shows the guillotine guideline to the right - a feature that is thought to be unique to this cover - and a "68" cancel.

It also includes a letter header showing an image of Ramsgate harbour in the UK.

A selection of British Guiana stamps from the collection of John Du Pont will auction on the same day.

We have an extensive range of British Empire stamps available, including this set of three original Perkins Bacon 1854 die proofs for the Tasmanian Chalon Head issue.