Well, at the thought of being boring , Can I change taps on a basin without draining down the whole combi system? Need to move two loo's and two basins!

Yes. the CH, seal system is separate. Just close / isolate the cold main supply and open the taps till they stop running.
If you were on the 2nd floor you could leave the water in the pipe work below that level once the pressure has dropped.

Thanks Raging bull
Just shut off main stopcock and crack on?

Paul jumped the gun a bit, sorry you will have to drain it to some extent, probably bad explanation.. once the pressure is out and the water is below the level you are working. No local isolation valves then?..

Obviously moving the loo etc will require draining more water.... especially with soldering involved, maybe a pain if pipes go up down up again.

No local valves, plumbing is a bit heath robinson! Used to a loft tank etc never worked on a full pressure system before! Still I will learn, just get buckets and towels out!!

While the waters off why not cheat. Flexi tap connectors with ball-o-fix valves make lift so much easier, and if you want to go really simple they also come in push fit

might just do that fatboy! bathroom basin and loo have a shut off valve but not the other loo! I need to move a shed load of pipe, so might just put two gate valves in the loft on H&C feeds to bathrooms while I am at it.