Timing belt issue

I recently got a Mitsubishi L200 Trojan K74 4D56 2006, and after getting through its MOT, I decided to do full service and change belts etc. I followed instructions from the workshop manual http://jdmfsm.info/Auto/Japan/Mitsubishi/L200/Manuals/ and checked with youtube videos, when I removed the lower timing belt cover, I found the mark on the crankshaft not lining up with the others, but assumed that this would be ok … Then I noticed the spring on the tensioner for the timing belt B (balance belt) had not been fitted correctly, and although the speedo had 130000 miles on it, it looked like the original belt??? So refitted new belts and new tensioner, and all went ok for a couple of miles, was just about to accelerate in 5th and the engine cut out. As I had not changed the fuel filter and was on my second tank of bio, assumed that it was a fuel problem, changed fuel filter, unblocked two injectors that were clogged with rust, but still nothing, called out RAC man and was told my timing was out, as I had back pressure at the air intake … As I had been unsure of timing marks I agreed, I have now spent over two weeks of trying to find the right mark.
The marks on the cam, injector and balancer I’m sure of, however I’m confused about the crank, there is a plate with timing marks inbetween crank sprocket B (back one for balancer) and sprocket A and initially was the only mark I was aware of, however I have now found a small notch in the back of sprocket B and tried to set timing to this, I have also found out that there may be a multiplier on one of the balancers (3 possible positions) and the crank turns twice to the cam, giving another 2 possible config, I have tried both and nothing, however if I turn the crank 240 degrees, 2x rotation of balancer the engine splutters as if about to start, it’s the closest I can get, am I missing something, obv I’m no mechanic but can follow instructions …