Ok, it seems Spink are getting confusing for the Chas I MMs. I'm looking in 2013 guide on page 272 and no wonder it gets confusing. On this page they have a list of MMs one of those being the crown MM 70 they have it listed on this page as 75 with date period 1635-6 and then on page 273 they have a slightly different varient of the crown MM and again its 75 but with a different date period of 1648-9 with Aberystwyth furnace, so 13 years in between both periods, no wonder it gets confusing with Spink..............2012 Spink also uses the same as above The Brooker book does'nt list the Shilling in there for the Furnace mint at all, only Halfcrowns, sixpence, groat, threepence and halfgroats are listed, it does however list the Aberystwyth mint itself, so i'm assuming these are different again because Aberystwyth mint has plumes on the OBV, or have i missed something? North is only slightly more clearer, with just a subtle difference between both crowns, where the middle (ornament?) of the London mint crown is more in the middle, whereas the Aberystwyth is near the bottom of the Crown I bet the civil war was started because of these bloody MMs