@jamesflint I use Desktop as my preferred method. Surface pressure isobars are just above the model picker: 4163f730-3674-470f-a173-5be711aae45e-image.png
Geopotential height unfortunately is buried a bit by swinging out the more layers menu:0ee9c42e-c8f9-43f0-bd2f-c30b3361d440-image.png. Oddly enough you can switch between isoline settings more easily on the mobile app.