OK, so you may still need a Darlington. Leave the 2N2222 as it is but disconnect the 10k from the base and connect it to the base of the extra NPN transistor. Connect the emitter of the extra transistor to the base of the 2N2222 and connect the two collectors together.

It is possible that the 2N2222 may get warm in this circuit. If it does then there is a modification that will keep it cooler.

Sorry to be a pain, but could you sketch this part out..nothing fancy just enough so I can understand and modify my schematic. Im trying to learn more as I go but slow. appreciate your patience with my lack of knowleage.

 

Oooppsss!
It occurs to me that with that 1.5V input signal there is barely enough voltage to turn on a Darlington. An alternative solution is required - probably an NPN and a PNP.

 

A sketch of the grounding circuit. The output load is simulated by 40 ohm R, RL. Input .8 to 1.5 V. About a 10 deg. F temp. rise on 2N2222
driver, 35 deg. F rise on RL.

 

My personal pref. is a TIP127, PNP darlington, 100V, 5A, B 1000, emitter to +12V, collector to load, & 3.3k between base & Q1 collector.
Input from .7V to 1.5 V. derived from 50k pot.

 

My personal pref. is a TIP127, PNP darlington, 100V, 5A, B 1000, emitter to +12V, collector to load, & 3.3k between base & Q1 collector.
Input from .7V to 1.5 V. derived from 50k pot.

A sketch of the grounding circuit. The output load is simulated by 40 ohm R, RL. Input .8 to 1.5 V. About a 10 deg. F temp. rise on 2N2222
driver, 35 deg. F rise on RL.View attachment 173551

Tried this at the weekend and worked perfectly....prototype now up and running on Veroboard. Thanks for your help.