Hi @Lucie,
Welcome to the Bunnings Workshop community, it is wonderful to have you with us.
Step one would be to remove any of the flaking paint and tidy things up. You can use a paint scraper to remove the bubbling paint. If possible, try to remove a paint chip around the size of a 50-cent piece so you can bring it with you in store to colour match it.
Once the flaking paint has been removed, put on a mask, then use a wire brush to remove the surface-level rust and sand the edges of the paint to remove any lippage with some 400 Grit Sandpaper. Wipe it down with a cloth to remove any dust from the surface.
You can then apply the White Knight Rust Guard Rust Converter. It works by chemically reacting with rust on iron or steel surfaces, neutralising it and converting it into a more stable compound that acts as a barrier against further corrosion. It will dry to a dark blue-black colour, which indicates the chemical reaction has taken place.
After this, apply a metal primer like this Dulux Metalshield Etch Primer Spraypak Light Grey, then allow it to dry.
You can then apply 2 coats of colour-matched enamel paint.
Remember to mask off areas where you don't want overspray or paint drops with masking tape and drop cloths or masking paper.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
