Mine ended up same. After I had a quick chat to Tim from Traxide, I didn't bother to test it, just recycled the Optima and replaced it with an SSB HVT70D (85Ah) from Goodchilds. It went straight in on the Traxide tray.
I did need a longer +ve lead made (AutoSpark Osborne Park).
Also needed a flatter clamp, purchased a standard one at Repco.
I'm in Wembley. You're welcome to message me and drop by for a look see.
(And I think there's a few threads on this very topic, if you want to see what others have done? Pretty much the same.)

