Hi again, have 2 x Deka 70 686MF 12v cranking batteries in parallel and one is half dead so unable to start truck up. They are 720CCA  and smallish 228mm (L) x 175 (w) x 206mm (h) made in the USA, maintenance free and heavy. The length and width are critical and height is not so critical. Maintenance free is essential as these are located at the inside of the pullout tray under the body. The house batteries are also here so do not want to pull out further than necessary just to top up the start batteries.

Have spent many hours looking and talking an cannot find any thing that comes close. Installed in a Mazda T4000. Any help with finding a suitable replacements would be most welcome. A link to a deka pdf where the sizes, specs can be found here http://dekavista.com/pages/duracell_specs.pdf