Probably not. You'll need to bring it indoors somewhere coolish or keep it in a frost free greenhouse or similar. I find that Pelargoniums will recover from a very small amount of frost, but I don't think fleece will give enough protection, especially if we SHOULD HAPPEN to get the amount of cold weather forecast for the coming winter.

If you don't have the space for the whole plant you could take some cuttings and keep them on a windowsill (root them in water this late in the season). For future reference the best time to take cuttings from Pelargoniums is supposed to be August.

There was some discussion on GoY a few weeks ago about another way of keeping Pelargoniums over the winter. You dig them up, shake the soil off the roots, wrap the whole plant, or bundle of plants in newspaper and put it on top of the wardrobe in the spare (unheated) bedroom. Various people remembered grandparents doing this.

many thanks for your advice