IAF Canberra T.54s had no ejection seats!

While researching an article about Indian Air Force Canberras I ran across the stunning fact (verified by 2 different IAF Canberra pilots) that the T.54s (otherwise identical to the T.4s of the RAF) did NOT have ejection seats for the pilots! The pilots just carried parachutes. The navigator strangely enough, had an ejection seat. I guess that was to make the navigator feel better about not having an ejection seat in the IAF’s B(I)58s!
Is anyone aware if some export T.4s were in this configuration? When the IAF bought the RNZAFs Canberra T.13s they were delivered with the pilots ejection seats.
My correspondents said they didnt feel like it was big deal because a lot of them had flown the single seat Vampire in training, which did not have ejection seats either!
Anyone here shed any light on why this was done? Financial reasons? Surely it would have cost more to modify the 7 odd T.54s to be without ejection seats than to just have them be in the standard T.4 configuration.
Also the IAF pilots do not remember ever referring to the T.54s as such – they were always T.4s to them, in the literature etc even though the other marks were referred to as full B.58s / B.66s/PR.57s and PR.67s