I have a 1950s with floorboards. It’s my second of similar age. In both houses the ceiling insulation and good blinds make them totally new houses in terms of comfort. Neither have/had anything under or on top of the floorboards and are comfortable. Have a look at the ceiling and any windows/drafts first.

I also would be checking the wall insulation. Is there any insulation between external timber and fibro sheets and the interior sheeting on the walls?

This article may be helpful. https://www.sustainability.vic.gov.au/energy-efficiency-and-reducing-emissions/building-or-renovating/key-principles-of-energy-efficient-design/planning-and-design/insulation/walls/weatherboard-walls#:~:text=Consider loose-fill insulation&text=This could be installed by,from above the wall cavity.

Thanks thats very helpful.

I doubt there is any insulation between walls given the age and type of home.

ill have a proper look in the roof space to check the condition of the insulation batts.

We dont want to do a massive overhall renovation of the house as I dont feel it will yield huge return for us. But improved energy efficency/comfort I feel is worth looking into. So thank you both for your thoughts to look into walls and roof first