DUB-REU-LDY-REU-DUB on a Wednesday is the only Thomson aircraft operating to REU on a Wednesday so it would be unlikely if that was ever a B757 as it would mean it would have to have come from DUB, which as I have already said is a A320 base.
James, during peak weeks at the end of July and into early August it has been, for the past few years a 757-200. There must be an equipment swap somewhere. Are there any 752 based at REU?