Excellent, we'll go ahead and do this then. Good way to use up the vouchers and not need to worry about chasing refunds..
In the end decided 55000 avios plus 568 quid for return to Madrid in business was better than the 1100 quid WTP ticket plus the 38000 avios (60000 minus the 22000 earned plus any extra taxes) was a better deal, regardless of not earning tier points for the redemption.