Y to G - what taxes need to be paid?

I have just upgraded a Y fare to G, are there any extra taxes to be paid? I was not asked for any.

I normally upgrade K or S to G so the taxes would the be same as I understand it.

Thanks

If you upgraded OUT of the UK, there are an extra £40 to be paid. Any other route, there are no extra taxes to be paid.

Hmm, no mention of that when I made the booking today with the premier team.