UK MD had no choice but to resign and you can definitely guarantee it was to spend "more time with the family".......
When you are in a position of leadership i believe it's best to behave professionally and avoid the little office temptations that present themselves to you because it will only end in tears, upset and resignations.
You can put all the BS around it you want and slate Avaya and complain about how "hard" it is in the current climate" but the UK is in good shape this FY and once an announcement ( any announcement ) is made the business will be even healthier.
So lets not blame Avaya but blame temptation and weakness !