looking for a proper replacement battery and my favourite supplier does not list 084 or 284 , wonder if there was a review of sizes since 1978 ?A Lucas battery Catalogue I have from about 1978 , as that's the latest application date listed , lists the same battery for all P6 models , but noting that a special battery clamp plate for where boot fitting is required ( Lucas 23282714) The batteries listed are either an 084 or 284 . The dimensions are L 240mm, W 175mm & H 217mm . The batteries are listed as 9 plate in a 7 plate case . 68 amp/hr