Posted: Today at 11:48
Unless there were some horrible chemicals in your shed one fire won't produce enough contaminants to spoil the soil and you could improve both the soil fertility and structure by forking in lots and lots of well rotted manure and garden compost. However, if you don't want ornamenta beds or lanw there's no point.
Decking can be expensive to install correctly and requires constant maintenance to keep the wood in good nick. It gets slippery when wet and also is an open invitation to rodents who nest under it. Pesonally, I think it's a bad idea in damp climates.
Large expanses of hard landscaping are also expensive to get right and, unless you use a porous material, can lead to drainage problems for the rest of the garden.
I think your best option would be gravel laid over a weed suppressant fabric. This would give you a clean area with good drainage and you can vary the texture with some paving slabs to support a table and some stepping stones and/or shapely larger rocks and stones laid through it. You can cut planting slits for specimen plants and use standing pots and troughs to vary seasonal interest and forms.
Select the gravel colour to tone with your hosue walls or provide a good contrast. Don't use too fine a gravel as this will just tread into the house. Slate chippings can look good, especially when wet. You'll need a border to hold the gravel in place at the edges and shoud aim for it to be an inch or two deep. .