Well, IO will give them something, at least they have not tried to BS the reasons for the allowance change in the email to me:-
"With regards to our Premium Economy new baggage allowances.
Virgin Atlantic has always offered an extremely generous free baggage allowance.
Firstly, we need to be consistent with other airlines when passengers purchase 'through tickets' requiring them to change airline in order to reach their final destination. It's confusing and frustrating for passengers travelling on different carriers offering different baggage allowances, and often results in unexpected expense and inconvenience should they find themselves carrying excess baggage after their journey has commenced.
In addition to this we must reduce how much weight we can carry in view of the ever increasing cost of fuel. We've taken the decision that it would be fairer to ask only those passengers carrying the higher levels of baggage to absorb the cost of the extra fuel required to carry it.
The new baggage allowance begins on the 23rd September 2009, as you made your reservation before this date you are able to use the existing baggage allowance for this trip.
Whilst your present feelings are appreciated, it is always disappointing for us to learn that a customer is unhappy, we are sorry that you are no longer inclined to support our airline, we recognise that you have the ultimate power to take your business elsewhere. Nevertheless, we sincerely hope that you will not do this, and in time you will have a change of heart and will choose our airline once again. "