People round us have electric showers in the loft because there's not enough water pressure, but they're shit and are currently a very expensive way to have a shower with the cost of electric.
A combi on its own is unlikely to give you good enough pressure, but you can add a tank to a combi system and if that doesn't work add a pump. Basically what @Howard said, that's what we had at our old place and I reckon it'll work.
But talk to a good plumber, they can measure your pressure (but we both know it will be crap at the top of the house) and advise on the best solution.
People round us have electric showers in the loft because there's not enough water pressure, but they're shit and are currently a very expensive way to have a shower with the cost of electric.
A combi on its own is unlikely to give you good enough pressure, but you can add a tank to a combi system and if that doesn't work add a pump. Basically what @Howard said, that's what we had at our old place and I reckon it'll work.
But talk to a good plumber, they can measure your pressure (but we both know it will be crap at the top of the house) and advise on the best solution.