Thanks guys, I wanted to make sure I wasn't missing a trick and it sounds like basically what I thought originally which is due to the age of the property the best we could realistically aim for is insolate as much as possible, fit good quality windows/doors, new combi/rads/controls, etc.
I'll have a look at the ventilation options mentioned too. With all the talk of energy saving I'm still amazed we can't only heat homes one floor at a time - it's the whole house or nothing which seems so wasteful. Surely in this day and age we should have one heating circuit for the ground floor and another separate one for first floor, etc. In-lieu of that I suppose the MVHR is a work around shifting warm air where you want it most, first floor at night time and ground floor during the day?