low cold water pressure

[breezy]

In downstairs clock room i have low water pressure, toilet takes ages to fill up and the tap just dribbles. Had new ballcock fitted, plumber said that the pipes would need changing to fix the tap problem as the pipes have furred up!
Cold tapes elsewhere in the house all ok. Is there any way of reverse flushing the pipes to see if there is some sort of restriction ?
Any advice appreciated.

[DONFRAMAC]

My home has 2 rising-main pipes-- one tucked away in the downstairs toilet room, and the other is in the bottom of the kitchen larder, feeding the main house. I had my bathroom renewed, with a major change to the upstairs toilet;-- it is now fed from low pressure water from the header-tank in the loft, as is the blender shower, and the bidet. The main point to be made is that the new toilet fitted had to be fitted with a cistern with innards which fills quickly with low pressure feed. Modern cisterns are also lower in volume than of old. SO--- a modern cistern of static-head spec. may suit., but fit a valve to throttle it by should it be needed. I fitted a hose-pipe tap with 3/4 BSP thread, beside my downstairs toilet, to snap-fit a Hoselox reel-out hose onto;- very handy for car-washing, etc.
What if your toilet room is fed independently, with its own riser;-- only a small task if furred pipes have to be tackled. I have heard of magnets which can de-furr plumbing, after being clipped to the outside of major incomers, but no doubt would take some period to be of some effect.

[DONFRAMAC]

I have recently had the misfortune to have to unblock one of our toilets. I flushed water thro' the soil down-pipe from the bath, sink, bidet, and the toilet, combined with a bucket-load of water into the toilet & bidet, + plunging the toilet, then bidet alternately;---- eventually the plunging of the toilet did the trick.
The problem that followed was due to me draining the loft header-tank, which feeds the toilet and bidet. Both became air-locked, resulting in very low flow. My investigations in the loft resulted in me standing on the 40 PSI rising-main incomer to the header-tank, and they parted company in a big way!!
An emergency call-out involving 1 hrs labour, got the tank coupling re-made, and the air-locks remedied. The bidet cold flow more than doubled, and toilet restored to normal (it had failed totally after 2 flushes).

The house RCD re-set a couple of hours later, but the next day the pull-cord light-switch in the bathroom had to be renewed ( £1.55).
POSSIBLE RELEVANCE----- YOU MAY HAVE AIR-LOCK PROBLEMS.
A garden hose can be used to route mains-pressure water into the pipes you suspect to be air-locked (briefly), to force the air backwards, out of the lines. Users of this forum have had some success with this.