There's a dozen or more detailed (inside and outside) pics of the Canadianicon No.4(T) Long Branch chest in the MKLicon.

1945 Enfield No.4 Mk1*(T) Long Branch Sniper Rifle (click here)

From the entry, go to the 160 picture photo montage and compare the chest pics against your C. No.7 chest and I think you'll have all you answers.

Personally, I don't think it's worth trying to convert.

Regards,
Badger