I got the point.
Searching Just Engines I found a review "A.S.P. 'Series 3' 1.80fs - RCM&E" of which I took an extract.
Quote.
The single ring piston is a permanent die casting from alloy, is of the slipper type and fully finished by machining. Internally it has two large webs to support the fully floating gudgeon pin. This has been fully bored, for lightness and is retained at the front by a semi blind hole in the piston. It is fitted with a PTFE wear pad at the rear, to ensure no damage is done to the liner when the engine is running.
This leaves us with the heavy-duty con rod. CNC machined from high tensile alloy. Bronze bushed at both ends, with a single oil hole centrally at the top for the small end, and two oil holes for the big end. Now it?s time to remove the crankshaft.
Unquote.
dogshome, if Your engines ara running fine they must have only two holes oil holes in the big end of con rod.