Fix for when Amazon Prime weekend deliveries disappear

Try this as posted above, it worked for me when my weekend deliveries disappeared.

1) On the basket screen next to delivery address with problem, Click CHANGE
2) On next screen click EDIT next to address
3) Slightly further down you will see : Weekend Delivery:
4) Click on this and you will see Sat and Sunday with a tick next to them (if they are not ticked, tick them - mine were already ticked even though didn't work)
5) Finally choose safe place if you want and click USE THIS ADDRESS at bottom 

This fixed it for me , Amazon must have changed preferences and for some addresses it was bugged as on mine they were already ticked however for this one address variation it needed me to do above for it to work.