Theres a lot to consider before the purchase.
The tank has to fit through the loft hatch.
The loft has to be easily assessable.
The floor would be boarded out.
The floor has to capable of withstanding the weight of the full tank say tank at 30KG + water 250Lt = 280KG.
The boiler flue would go...
Can we have a forum dealing with legal issues.
The legal issues that few people know but everybody should be aware of.
It might be a minefield but it would be lively.