Charles Portway (Victorian) sales brochure
Charles Portway sales brochure
Downloaded from the current Portway website (at least I thought that was where I found it).

The Portway stove is likely to be similar to model 7 in the brochure shown above and retailed for £6 and 16 shillings (unfortunatly the date of the brochure is unknown)
A current price taken from an ebay listing for a No. 2 Tortoise, fully restored, was £1,350 (plus 150 postage). The photographs on the listing included a page from a sales brochure.