I have two rescued dogs who were both housetrained. We have had them approx 4 years and they have recently started messing in the kitchen. We have a large garden which they have free access to, but they are messing even when they have just been out and on one occasion, right under my nose while the door was wide open. They are both healthy, with access to water at al times and fed twice daily. Nothing in their routine has changed. At first we thought it was just one dog but now they both seem to be at it. Please help

I have a getrman shepard and trust me it would NOT work out if he did that!
First thing in the morningtake your dogs out for a walk . Within 5-10 minutes after the meal . Then when you come home from work (if you do) if you don't then Take your dogs out after being played with for awhile. This is very stimulating to many dogs and they will need to eliminate soon after something exciting happens.
Also make sure you wash your stuff A lot because once a dogs found a spot with their sent on it, they'll try to maintain it.
Hope this helps,
Kristine :)