Shower pressure issue

[Vic8710]

Assuming the other cistern in the loft is also redundant, the neater way would be to cut out the redundant pipework in the loft altogether (without leaving a dead-leg) and connect the gravity pipework to the mains supply downstairs, assuming you have a minimum of 15mm diameter pipe on the existing gravity cold. It would mean your isolator would be in an accessible position and you might then find you'd be able to get rid of the pipes in the loft, but it won't make you more intelligent, more attractive, or stop you gaining weight (or was that an old tobacco advert?). Depends how close your gravity cold pipework comes to your mains pipework and how easy it is to cut out the deadlegs. It may not be a reasonably practicable solution at this point in time.

My plan was to join the two pipes together in the airing cupboard(to the left) just like what was done with the hot water pipes in the right of the picture below. Once hat is done i could get rid of all the piping and the tanks from the loft.

 

[Ric2013]

Yes. If there are no branches, then that makes sense.