I'm thinking of purchasing Avios using the 50%bonus (don't have an eligible card) to then UUA myself and my wife to CW from WTP on a MAN-LHR-JFK EWR-LHR-MAN
Is it worth doing? Vice the cost of doing it in cash? And if so how many would I need? I only have about 2500 gained through clubcard points. Which is a major frustration as I had a Lloyds Bank amex and I've never been able to find the Avios I earned on, that!!

Thanks