Psu for Dome Node.Esr Components/Quasar Electronics now stock the Ceebek 5v and 12v switched mode regulated supply module boards. These do have a far larger heatsink than the Velleman VMA404 modules. Only breakpoint is the price - just under £22.
For the regulator overload protection either refer to the regulator’s datasheet or the following circuit suggestion.
There’s also a 2 transistor analogue circuit that has been used in battery charger circuits in the past. It’s action tends to be a cyclic on/off (to several MHz) as the current limit figure is reached. A capacitor can be placed between the 2 transistors (across the driver transistor C-B junction) to suppress high frequency interference. Have seen this circuit referred to as an electronic current limit. A disadvantage is that this current regulator drops some voltage as well.
Found a 100VA sub-minature 12/15 volt tapped transformer on Jaycar’s website. Have purchased for a power tool battery charger. Import duty was heavy though.