I'm thinking of using up some stale bread for my dinner later. Looking at bread sauce recipes they all seem to call for bay leaves onions etc. Would white sauce plus breadcrumbs work okay or be a bit bland?

It would just be stale bread mixed with milk essentially, so yes, very bland indeed.

Milk infused with onion and cloves, mace is good but optional, as is double cream to finish off.

Didn't have any cloves or mace but used the onions plus garlic and some peppercorns. Also added butter at the end. Turned out quite well.