I have come to the conclusion that the exact position of the drilling for the levers is specific to the shaft to which they were originally fitted. In other words, when trying to marry up odd spare levers and a replacement shaft, the ends of the levers will not be in line (unless you are very lucky). Obviously if only a small amount out, then one of them can be filed to match.
If you eventually give up trying to get the taper pins out and hack the shaft out with an angle grinder, you will need to rob the replacement as an "assembly" from a donor gearbox rather than go looking for loose parts.
The original pins have a 1 in 48 taper. Metric replacements will have 1 in 50, so a taper reamer may be needed and you need to know which type of pins you have bought.
Ron

Location: Thornbury

Thanks everybody for your help and advice. Much appreciated. There is no urgency so I am giving the duckoil a good time to work.
Happy motoring/spannering
Graham

Location: Angus