I recently had an ensuite installed which consists of a power shower, sink
and loo. The hot water for the shower comes from the main hot wter tank,
whilst the cold for all 3 comes from the cold water tank in the loft.

Recently there has been no cold water supply i.e. the shower "struggles", no
water out of the tap and the cistern fails to fill. I have managd to get a
tube with a cloth round the end for a seal to blow through the pipe in the
cold water tank feeding these, which forces water through to e..g the tap
and cistern ok suggesting no blockage but then the situation reverts to no
water.

any ideas gratefully received as to what might be causing this and any
solutions - the recent plumbing has been done with push fit connections

thanks
Cheers
Chris