Just a opinion but the OTW hull looks to have a bow more like a Resolution class to me. The Valiant and sister ship Warspite both appear in the pics I have to have bows similar to the Churchills.
Just an answer to the Ohio Vs Vanguard question but as far as I am aware the Vanguard class have pumpjets and the Ohio class subs do not. Pumpjets as far as I am aware have a better power to thrust ratio than normal props.
All the best,
Peter W 2731UK