Many Thanks for the responses, & action.
Clearly, paying in US $ for UK Purchases, is not decent value, due to the decline in the £ in all currencies. Fares are also priced for the local market in the UK, or travel from the UK.
So far as i understand, Payment protections, insurances etc, are also not covered unless it is a UK registered Company.
Booking on Travelocity.co.uk would cover, payment in US$’s on the link would not.
Thanks you for providing both options, though the days of being able to purchase, & depart from a different country are gone, with the value of the £ so dire it is no longer viable.