A+ Engine & Gearbox conversion

Have fitted an A+ engine and gerabox to our 64 Elf. To mount the rod extension I cut a hole for the gear lever, hammered a couple of flats in the round tunnel and then drilled a hole in each for the bushes to bolt to. 3rd, 4th and reverse are a doddle but the lever has to banged over hard to engage 1st or 2nd. Can anyone advise if this is likely to be a problem with the mounting or with the geabox.
I note from the other topic on this subject that changing the entire transmission tunnel appeared to be the preferred option. Any help appreciated.
Hope to see some of you at Bromley. Kind regards.

Why not simply modify the original mounting bracket to a more "rounded" shape. Drill the tunnel as needed and bolt it on using the standard bobbins. It'll be a much better fit.