Weber 151 drilling defect

[ChrisGibbs]

Full disclosure, not a Lotus Owner but after much research you and the Alfa boys are the Weber gurus so thought I would try my luck!
Trying to correct the poor idling on the 40 dcoe Webers I am fitting to my BMW 2002 , I had checked the usual suspects (compression 140psi all cylinders, new NGK BP5ES plugs, good spark, 2.5psi Fuel pressure, float level correct, checked for vacuum leaks with ether, runs on all 4 above approx 2000) but eventually decided to partly dismantle and I noticed that there is a missing drilling in the starter circuit (see attachments) Notice in the first photo there is a missing drilling at the top of the starter valve bore. I won’t be using the starter circuit at all, however I’m not sure if this may be my rough idle as the problem is on the carb that has the non drilled hole and not having it there may be affecting the idle circuit somehow. And yes they are brand new Spanish Webers.