Wet patch on living room wall (outside wall). Chimney has been repointed, checked outside gutters and in the loft as well as roof tiles. It's a bungalow. Any other ideas please?

When the chimney was repointed, did they renew the flashing?

Any plumbing in that wall? Back to you, Tom

Were the patches appearing BEFORE the chimney construction ?

Chimney is the #1 source of roof leaks. Moisture barrier has to be tied up into existing roof so it diverts condensation away from the roof. Also, "cricket" is a must. Lastly, "Z" flashing must be installed in combination with Step Flashing. Any of these omitted will result in leak.

Please, check with you builder to make sure building Codes have been followed and proper materials have been used during construction.

Back to you... Milo