1974 Other Jaguar Models trying to get an old engine going a

Hi there from Australia
I have recently aquired a 74 daimler double six and im having a few issues trying to get it to run.
The old girl was owned by an older english gentleman and he bought it new, drove it for 50,000 KM's and when the battery went flat (activating the central locking kit) he never drove it again. Still has running in oil!
But regardless everything was in good condition when I opened the bonnet except for the vacuum hoses were slightly perished. None the less I have replaced all of them, the spark plugs, and leads and originally I had no power from the coil. Simply I jus ran a direct line to the coil temporarily. My issue is that when I turn it over it will run very lumpily and will not rev, rather backfire. But I have had the carbies off and all of which had stuck needles (float chamber needles) so I cleaned the carbs and left everything factory except replacing the needles obviously. But the problem now lies that on the r/h side bank it runs smooth without a problem. On the left side it misses but is still firing on each individual cylinder. Seems almost as if the timing is out. Strangely when its running it backfires out of the gulp valve pipe that returns to the air filter.

Another strange tidbit is that the vacuum hose was missing off the dizzy, but when I went to replace it mine seems two have a two way diaphragm. It looks the same as a normal retard one but mine does both advance and retard, could this cause any issues?

I keep coming up with dead ends as to where to go.
Hopefully u can help me nut out this problem

Cheers