Good to see you back, RodneyB!
So, let me get this straight:
You're using 2 x 1.2 VDC Nixx batteries (presumably in parallel to get 2.4VDC), whose output you are then regulating down to 1.5VDC. Is that correct?
And you the want a circuit to charge the 2.4VDC battery set, right? I ask because in your first post you asked for a 1.5VDC charger circuit.
In either case, Try GOOGLING "nicd battery charger circuit diagram" and take your pick...
We'd be glad to critique your selection and offer suggestions.