Loft conversion - feed the shower?

This is a possiblity if you are replacing the boiler anyway. An instantaneous non-storage combi will provide excellent showers, but will be less good filling the bath. This won't be an issue if you mainly take showers, although you will definitely need a high flow version if you want both showers to work simultaneously. There are also storage based solutions with a small unvented cylinder or heat bank within the boiler casing. These will provide reasonable bath performance, too.

Choke. Splutter. Cough.

I put a DPS Pandora heat bank in. I haven't converted the loft yet, but this will be ideal when I do.

You may be able to use the existing hot water system with the right array of pumps, switches and check valves. The shower would almost certainly need a "kick start" switch as the head would be negative, so flow switches won't work (except to keep the system on until you've finished).

Christian.

Disregarding the loft, it sounds as though you already need a much larger hot water tank.

We fitted a power shower pump and quickly emptied the hot water, and so had an extra large copper tank fitted. This now manages to service two power showers at the same time.

As already posted, your conventional system can work in the loft as long as you have a way to 'kickstart' the pump.

Beware the 'combi' debate :-)

HTH Dave R