Filling it up with very small gravel might help (not a cheap option, though!), and encasing the underside and gaps in a couple of layers of very fine mesh (you can buy Mouse Mesh), at least against the larger unwelcome visitors (rats and foxes), but you will have to resign yourself to probably having mice, I'm afraid. As previously stated on this thread, ensure you keep all food scraps etc out of the garden (unfortunately bird feeders etc will contribute, make sure you clean up the ground below them daily), and keep the area clean and tidy. If you do find mice or rats, call the council immediately and they will send someone to deal with it. Some councils will do this for free, but others charge a small fee for private properties. Worth noting though that they are usually cheaper than the commercial firms, and come back free of charge within a certain time period, if you have a return of the problem! Finally, make sure that you have had a good go at mouseproofing your home - if you give them somewhere to live in the garden, they will then try to get into the house once the weather gets cooler. Seal airbricks with mouse mesh, fill small holes with sand cement and steel wool, and so on. Personally... I'm getting a patio!

Hi Emmeline, We completely agree with Aye Gardening. Softwood requires maintenance, and if you do not have the time to keep it good looking, we recommend you go for composite decking, such as Millboard. We have also seen some amazing transformation with Millboard Composite Decking, as it requires very little maintenance, it has good slip-resistance, it doesn't age, and can be used in damp areas as well - such as pool surrounds. Have a look at more photos here: https://www.houzz.co.uk/ideabooks/81725744/thumbs/how-composite-decking-can-transform-your-outdoor-space  Kind regards, London Stone

I was one of the original poster. Eventually in our case, building control wouldn't allow this - they originally OKd the plans, but then wouldn't allow the removal of the ceiling from the box room. There was a "galleries" approval that we explored but they weren't having that either.

Hi Betty, it came in kit form, so a sturdy plastic pond inside and then you build the wood surround around it following their instructions, and then I painted all the slats. Quite a lot of work but I love watching the fish, so very restful! Look forward to seeing the raised bed when it’s all done.