UPDATE
Got the firing order sorted out, was told that No.1 was at the four o'clock position on the disributor cap and to work anti clockwise from there which sorted it out but I also found that the distributor arm was out and not matching up with any position at all!
Next problem is the reason I initially took all the plugs out, that is 4-2 are miss firing. All plugs were cleaned, all have a good spark, 1-3 are working fine. I have swapped the HT leads, they are fine so presume it is a fuel problem. I have notice that the carb is leaking more than usual and have found a puddle of fuel underneath after turning the engine over. Have considered head gasket is perished but from my limited knowledge the engine oil may be contaminated if this is the problem, but it is still fresh.