I put my keys in the microwave!  I have my car key fob on them and been advised to keep keyless car fobs in a metal box to stop any signals detecting them.

A microwave is a metal box as good as any.

We have a door key each which are in his pocket and my handbag.
We have a spare door key which we use to lock up with and leave it in a dish not far from the door but out of reach. Said dish also contains a key to the porch, one to the shed and various window keys. 

Darley, but when you go out, taking your microwave is a bit of a faff. You still need to protect your car key if you go out. Eg, I often park in a particular office car park and am in the building so there is a risk there. The Faraday pouches we have are a bit more portable!

Darcey, sorry!

Barmaid - Barry asked what we did after locking up for the night, I take the keys with me when I go out as it has front door key on.

Did try a Faraday pouch but friend who is a police officer said they lose their strength over time so you must keep replacing them.