Seems sound, similar to an issue I had with a Gottlieb once. But that 0.5 amp can make a difference, be worth upping it if you get further blowing before investigating further - and avoid the cheap Ebay fuses, they seem to be more a problem than a cure from member reports.

Yeah Nick .. will grab some probably from Greg when I place another order .. just bought some parts from him .. unfortunately before this problem surfaced .. Jaycar (or Dick Smith)  don't stock the 2.5A SB in 3AG .