Merton bread does not contain any preservatives so here’s a guide to how the bread lasts if stored correctly.
The first two days the bread will maintain its characteristic chewiness in the crumb. If you squeeze a bit of the crumb between your thumb and forefinger you’ll see how it bounces back.1 In those first days it is perfect for eating fresh. Into the third day the bread becomes perfect for toasting, and will remain so for 5-6 days. After then try some ideas for using stale bread.
Another idea is if the loaf isn’t too old then you can actually heat the bread (just to around 60ºC) and this will freshen it up again. In fact, this more or less mimics what toasting bread does.
If the loaves are a little big for you and you are worried about them going stale, just cut in half and put one half in the freezer in an airtight bag. It will keep in the freezer for 4-6 months. When you defrost it, it will not be the same as having fresh bread (all foods degrade in the freezer due the formation of ice-crystals which slightly damage their structure) but it will be yummy all the same.