Lag which exposed pipes in cold downstairs toilet

[JamesA]

The downstairs toilet has:
the back external wall facing the prevailing wind
the left wall to the integrated garage
the right wall external to the front door where there is no porch.

The room is cold and condensation occurs on the cold pipes.

The pipes are white and the wall is white, and so I’m thinking of buying some white foam lagging.
With the gap between the parallel pipes the cheaper foam lagging will fit fully around one pipe and I’ll cut a third out of the other bit so it can fit up against the first lagging.

Is lagging both hot and cold the best approach, or given it’s a cold room should I just lag the cold?

Condensation on the toilet tank itself doesn’t seem too bad, probably because we don’t flush the toilet all the time and so the water reaches room temperature rather than 6 litres volume of cold water being introduced into a warm room every few minutes.

 

[JohnD]

all of them

and:
cold wind can blow in the overflow pipe. A short-term fix is to have an elbow dipping below the water level in the cistern, a better solution is to fit a new modern flusher with an internal oveflow that drips into the pan, and remove the old overflow pipe.

 

[JamesA]

It does have internal overflow (bought DIY shed about 4 years ago).

Other information:

Walls have wooden cladding half way up which would make it difficult to know if old overflow pipe hole had been sealed well, so I better check the outside...

House 1990 plasterboard.
Previous experience leads me to believe none of the pipe runs under floors or behind plasterboard are lagged.

Radiator valves adjusted to be fully open.
Even so, room tends to be 2/3 degrees colder than other areas which I think means I also need to heat the house a little more as it has dropped as low as 14-15 degrees on occasion when the living area reaches our minimum of 16 degrees.

Mains water stock cock is also in the toilet.

Garage door is insulated(DIY job, not brilliantly) and also lets a little draft into the garage. Don't have garage temperature readings.

Toilet upvc window not covered in condensation in the mornings.

Like many people we're walking a bit of a tightrope between energy bills and condensation.
It does seem though as if the toilet is a weak link with it's lower temperature not being able to hold the water vapour in the air.
Otherwise the relative humidity is just about ok until the temperature rises in the day or ventilation occurs.