Rats, space constraints mean that I can't do the system with stacked cylinders within the house

So now my choices are:
A) The pair of 140L cylinders in the loft (above the wood stove and near the panels) OR
B) A proper thermal store, but outside somewhere.
B) still isn't looking likely due to the cost, really.
And the whole MCS/RHI thing is putting me off doing anything, even though I have most of the bits
