Draughty loft hatch — best way to seal it without making it hard to open?

[SawdustSparrow]

Hello all. Our loft hatch lets in a noticeable cold draught in winter, and I can feel it standing on the landing below. The hatch itself is a fairly standard hinged board, but the gap around the frame looks uneven in places.

I would like to seal it properly without making it awkward to lift or causing the catch to stick. Has anyone had good results with foam draught strip, a brush strip, or adding a layer of insulation board to the top of the hatch? I am also wondering whether it is worth sealing around the frame itself first, or whether that is likely to make very little difference.

Any practical tips on what worked, and what to avoid, would be very welcome. Thanks in advance.