Inserting replacement B44R petrol tank 42-8052 rubber buffers

[B44R Victor]

Just replaced the left side petrol tank rubber buffer and had quite a trial.  I finished up carefully giving it a few short sharp thumps with a hammer to drive it home through the hole in the frame but I was hesitant doing this so near to the coil.  Fortunately I got away with it.  Now I've got to replace the right hand side and wondered if there was a better way to insert these through such a small hole?   

[Beesy]

Maybe try warming it up to soften it? Drop it in hot water for  few minutes. Could also try a dab of washing up liquid?