Ah, ok. I was way out with my assumptions on time lines,...

Ah, ok. I was way out with my assumptions on time lines, definitely wasn't thinking years for the FS.
I think early exercise is not an option, unless they have done a deal with management to exercise a portion for drilling costs etc.
They would want to be pretty certain of the project before tipping in that sort of cash, hence the 3 month period after FS.

If they are indeed buying now, I would imagine part of the reason is a hedge incase the SP is 20c (example only) at the time of exercise, i.e. in 3 years they can sell these 1.5c shares to fund the exercise of the options.

If they are buying and also exercise early, hugely bullish I'd imagine!