I fly for an airline out of Newcastle so thought I'd give an insight into why MME is no longer used as a diversion.
When planning our flights, we have a fuel alternate and several commercial alternates. The fuel alternate is primarily used to allow us to depart with a lower fuel figure (commercial realities!). A commercial alternate will be chosen if there is a strong likelihood of a diversion It will be typically a base or company destination as the facilities are already in place to help on the ground.
We used to plan MME as a Fuel diversion because it required less fuel than EDI. I've also diverted into MME twice when NCL was closed (snow).
Unfortunately, due to the variable Fire Fighting Cover and limited opening hours, MME doesn't even appear in the company lists as a diversion airfield anymore. My last diversion (due to a thunderstorm) was into LBA.
Will this ever change?? The words chicken and Egg come to mind!
It's such a shame to see MME as it is - I did my PPL, instructing and some biz jet stuff there before moving north.