JMC only have 2 A330s on order! The first will be delivered in November, the second in March 2002. One based LGW, the other based MAN.
JMC did look at the B767-400ER, and the -400ERX. The -400ER does not have sufficient range to carry a full load of passengers non-stop from the UK to Florida, Mexico and the Carribbean, especially under adverse conditions, or from shorter runways such as Birmingham or Newcastle. They were however interested in the -400ERX, but there was still uncertainty around that programme when they ordered the A330, and the A330 offered much earlier deliveries. Since the B767-400ERX has been cancelled, looks like JMC made the right choice...