Personally I would never put an optic on an SMLE. Historically this rifle was rarely scoped, and even though there was one sniper version it was not really favoured and rarely seen. An Enfield No4 on the other hand, i would love to see an airsoft version scoped one day (G&G im looking at you), but this isn't that model sadly. Also drilling some modern rails on this 100 year old rifle, is just a big no from me lol. But that's just my preference.
If you really wanted it, at a push i would suggest this configuration but would be very difficult and expensive to fabricate.