I had the same issue recently, 
Check the back of the ignition switch to see if you have power at the constant ignition circuit, if yes check power at the fuse box ( both sides of the fuse ).
Theres two circuits for the the ignition, a 12v starter circuit so when you hit the stater position on the key the coil gets a hit of straight 12v to give a better spark for an easier start. The 2nd circuit runs through a resistance wire to supply around 9v to the coil for constant running, this lower one i believe is used so your points last a lot longer.
I had issues finding the resistance wire so i ended up rewiring the circuit through a ballast resister and disconnected the original wire.
To test this throw a multi meter on the positive coil side whilst cranking which should show 12 volts, when release the cranking back to ignition you should still see around 9 volts.

Thanks guys! Will take on all the advice and report back when I get a chance to work on her again :)

Still troubleshooting, today checked the dizzy firing order and timing and all looks ok.
 
I did notice that the pink resistance wire heats up considerably under accessorie and cranking, any idea's why this could be happening? I will try and get some photos up in the next few days.

It could be that the resistance wire is stuffed, There shouldn't be power present at accessories but will be at cranking and ignition, as a test bypass it from where it starts to finishes with a standard wire.
If the car runs like that then you need to replace the wire, a note though you can't run the car like that around town as you you will burn out your points quick smart and not sure but dependent on coil you could have heat issues with that as well.
If you can't get a resistance wire than you can replace it with a ballast resistor (mine cost 6 bucks) which works on my car a treat.

Thanks Mickos.
 
Here are a few photos of the resistance wire and coil:



This is the resistance wire connection point.
 
 

Just try bypassing it as a test, it may look ok on the outside but 30+ year old wiring can be crappy on the inside.
If you have a multi meter check the volts on the coil of the resistance wire with ignition on, from memory i think it should be max 9v and min 6v, i could be wrong on those figures but someone else may give more accurate.
 

So by by-passing you mean disconnect the current resistance wire and replace with standard wire? Before i go and run an new cable, on the coil (-) i have black cable from dizzy connected and on (+) i have a red/green wire then connected to that i have two pink cables connected together as the photos i have posted in my last post, is this correct?

Just connect a wire to where the resistance wire starts and where it finishes, effectively having two wires connected at the same time just one not cutting the voltage down. You don't need to disconnect anything. If the car was running ok prior to your fuel pump issue then odds are the current way its wired is correct.

Thanks, will give it a shot. I bought the car in 100 pieces so has never worked under my ownership :)