Why not try cutting up pieces of sandpaper and glueing them upside down on the decking. This would provide a non-slip surface and if different colour sandpaper were used would also look very pretty. Hope this helps.
[quote="Gumpy"]Any advice on how to cure decking with frost on it please[/quote]
To find a cure you have to have preventative measures in place. Frost happens when condensation freezes. The only way the reduce the frost on your decking, is to either cover the decking with a tarpaulin at night and lift it in the morning, or do as what contractors do to car park areas at shopping malls i.e. gritting the deck with course salt. This might not be the ideal solution, as salt is bad for plants. The third option I can suggest is to pour warm water onto the decking in the morning before you want to use it.