In the light of the helpful comments I am reassessing how I tackle this. I am thinking if I am going to make a linear regulated supply that it needs to be far less adaptable and more specific to its main purpose.
Additionally I am thinking of buying a cheap LED SMPS, they are only about £15.
Are these sort of units likely to fail to high voltage, I would think if they fail they would go to zero output. They are supposed to have short circuit protection.
"Input: AC110-220V 50/60Hz
Out put: DC 12V
Protections: overload/ over voltage/ short circuit
Cooling by free air convection
(Not suggest for use in bathroom)
Connection:
L, N: AC power input
GND: DC power output "-"
V: DC power output "+"
+V / ADJ: Adjust the output voltage
Safety Compliance: CCC/ FCC / CE"
Has any one experience of these.
Mike