Bubbles & Champagne

Long time no post
I'm T-13 for LGW-LAS and at T-90 I grabbed (requested) two Econ seats in "The Bubble".
Was extremely happy with this, until the other day, whilst working at Gatwick Airport I got chatting to two check-in girls.
I said I was looking forward to the flight as I had seats in the Bubble.
It was greeted with grimaces from the girls and I asked why. They both said, there was a very big chance of getting moved out of those seats if the flight is not full. This was due to weight loading/distribution. I felt kind of despondent, as was looking forward to my first ever flight on an upper deck. Looked like it was commonplace on less than full flights
Now looking at the flight, Econ looks nowhere near full, but PE looks fairly rammed.
J0 C0 D0 I0 Z0 W5 S4 K4 Y9 B9 R9 L9 U9 M9 E9 Q9 X9 N9 O9
So do you think that, as there would be nowhere to move the PE folks to, they would also leave the Econ alone too up there??
Secondly, is there anywhere to prebook and pay for Champagne online/phone before we fly out??
Many thanks in advance y)

I'm T-13 for LGW-LAS and at T-90 I grabbed (requested) two Econ seats in "The Bubble".
Was extremely happy with this, until the other day, whilst working at Gatwick Airport I got chatting to two check-in girls.
I said I was looking forward to the flight as I had seats in the Bubble.
It was greeted with grimaces from the girls and I asked why. They both said, there was a very big chance of getting moved out of those seats if the flight is not full. This was due to weight loading/distribution. I felt kind of despondent, as was looking forward to my first ever flight on an upper deck. Looked like it was commonplace on less than full flights

Now looking at the flight, Econ looks nowhere near full, but PE looks fairly rammed.
J0 C0 D0 I0 Z0 W5 S4 K4 Y9 B9 R9 L9 U9 M9 E9 Q9 X9 N9 O9
So do you think that, as there would be nowhere to move the PE folks to, they would also leave the Econ alone too up there??
Secondly, is there anywhere to prebook and pay for Champagne online/phone before we fly out??
Many thanks in advance y)