Hi Nina, we breed Siamese and also have a pure bred moggie
Our cats are all indoor cats,however we are fortunate that my other half knows his saw from a paving flag and so we have cat runs adjoined to our back room window. They have heated quarters in which they have constant access to water and biscuits and can snuggle as well as a toilet area and they have loads of room to excercise or just sit and put the catworld to rights in the sun(when we have it
) and they can be safe,still get fresh air and enjoy being cats too
We also gave them toys and various objects to keep them active and theirs room for us to sit out and keep them company
If your garden is big enough maybe this would be an option for you and yours,better if someone you trust could build it for you as it's slightly less expensive and you can have it built to suit