Hot water / have heating system help

Hi,
I am just buying a new house and need some advise on the heating system.
Currently there is a open top cold water reservoir in the attic, and an insulated cylinder in the kitchen (part of a old flat roof extension). There is a external oil boiler just off it.
We want to reclaim the space in the kitchen and were considering moving that tank to the attic.
I've read up on the issues with moving the insulated tank to the attic and having to raise the cold water tank etc.
Is there an all in one system we could upgrade to? (removing both the water tanks and the boiler)
We intend to go solar for energy so happy with a full electric option.
Whats the best way forward? What's the most cost effective option?

There are many ways of skinning this particular cat and tbh your best bet might be to approach a good local plumber or heating engineer to determine what might work best for you. For instance, you could change from open to sealed ch system plus pressurised plumbing or to a completely different system such as an air to water heat pump.
Also, don't forget that the heating system is only half the equation; are there heat loss opportunities you could easily go after? (which could then influence the heating system choice).

If you end up having to replumb the pipework, I strongly strongly recommend that you future proof your pipework, by getting the plumber to use 32mm pipes for each of the main runs. This will allow you to upgrade to a heat pump later without having to do any pipework.

Also, for any radiators that you are replacing (or new ones that you are putting in) size them up so that they are appropriate for a heat pump.
And also the new hot water cylinder, make sure the coil is compatible with a heat pump.

For a retrofit heat pump, the pipework and radiator upgrades are usually more than half the cost. Doing them now, will mean upgrading later will take a lot less time and cost a lot less money. It might cost a few hundred extra to do these upgrades now, but could save you thousands later.

You could also consider going straight to heat pump, (I'd definitely get at least a quote) but if you want to get the grant, you will likely need to upgrade the insulation and windows.