I have contacted the Eurocarb spares website, found the following:
Ebay o rings are not the correct size, genuine o rings ordered, fuel was leaking around the pump jet past the o rings
2x check return valves underneath the top cover have ball bearings and weights in, any dirt will allow the fuel to leak past causing the drip, I have cleaned these and leak stopped
Genuine float valves that are coated in Viton are much better than cheap imitations..
I hopefully will get all this fitted the weekend and find out if it resolves my rough running engine, combined with float level setup and a 4 way manometer I am hoping she will finally run correctly..
Hope this helps anyone suffering with rough idle..