I had a paid economy reservation for 3 people for LHR-VCE for next August. This was an add on to an F award reservation from JFK-LHR since there were no award seats LHR-VCE. When I booked, economy was £200 and Club Europe was £700 so I booked economy. When checking the reservation yesterday, there was an upgrade offer of £69 each. I jumped at it. Do these offers happen frequently?