The A340-600 last year operated 3 weekly LAS and sat on the ground at MAN for the 4 days it didn't run LAS. It seems the A330 is going to do the same this year.
The A346s were surplus and on the way out as the B789s came on stream, seems to me a little odd to have a non maintenance extended parking of a new-ish A330. We shall see what transpires....
Could pop up to GLA and do a few extra MCOs/CUN/BGI etcs
Indeed, it's peak summer and they're paying to lease these aircraft!