The seat is quite odd. I have trouble seeing how it all works??
I can explain the seat Sue (and anyone else interested) as the bike and OP are in the same State as I.
Queensland allows a substantial discount on overall registration fees (registration and compulsory insurance) if the bike is modified to single seat.
The discount used to be 50% but that has eroded over the years, but it is still worth having.
The other thing that has changed is the requirements to get the discount - back in the early 80s you had to shorten the seat, remove the rear footpegs and render the mounts incapable of having footpegs mounted - which effectively meant drilling out thread in an alloy mount or welding up[ a steel one.
More recently the requirements have changed again so that it is self assessment and simply remove the rear footpegs, the self assessment relates to the "effective length" of the seat. Because I'm a fat bastard I self assessed the unmodified seat as meeting requirements, that is to say nobody would be able to get on the bike with me.
I suspect that the OP's bike was modified during a less liberal phase and the seat foam cut out to shorten it but as the cowl is bolted to metal it was left in place.