Looks like a really nice place.
EPC of F - not good with an oil boiler.
First thing would be to investigate the cost of upgrading it to be cosy... Cavity wall insulation (If possible), Loft Insulation (How much now, and how much to upgrade). Then are the Windows energy efficient pilkington-K/ thermal type class?.
Stage 2 - now you are not leaking heat into the world :) - would be into investigating the boiler and finding out if it could be replaced with a more efficient unit. Or would it be more efficient moving to LPG? (Or mains gas subject to availabilty/cost or ground source (they can be horizontal if a big garden or vertical if the geology in the area is somewhere the earth has Lava closer underground) or air source (but they have many, many shortcomings).
Stage 3.5:
Depending upon your electricity supply, and if you can get a duel-tarrif for either an electric car (Even if you don't have one), or a night-time lower rate (In the UK it;s kind of "Economy 7" type arrangement - Don't know about the other side of the Irish Sea.
If you can, look at the orientation of the propert and determine whether sloping roof space is mainly southerly. If so, look into getting a battery wall (Which you charge at night when it's cheaper, as well as running dishwasher / washing machhine / tumble dryer if possible during the lower rate)
If suitable for solar, they have become sooo much more efficient and cheaper in the last 10 years. What used to cost £200 is now £50 in terms of materials (Labour is a differnt thing).
Worth considering taking any excess energy from solar cells either to charge the battery bank, and then divert into a heating coil in a hot water cylinder.. "Every little helps"
Hope this little rant helps you, or anyone else..