From my understanding and I am just guessing Chris wanted to put a better Nova signal into North West England to make it more commercially successful there.
As for IOMIB and I'm sure Paul would have much more information than this enthusiast, but it is my understanding they wanted a signal to get into London and the South East as this would be better for the Sales people and the RTE/Atlantic 252 transmitters had the Wicklow mountains and Wales in the way and affected the quality of the transmissions into the more commercially desirable areas like London and the Midlands. Where's a platform on the sea would help the signal like Offshore stations.
From what I recall the LW signal into East of London was reasonable to poor, but obviously a great signal for me as an anorak. Ordinary folk would have probably disagreed and think they never poster advertised down this way for that reason.