I am trying to finally get my bathroom extraction sorted, since there is no point in getting a dehumidifier and then pumping shower steam into the hou se ! So ...
Be careful buying "five inch" ducting. I got a previous lot from TLC and it was all 125mm (it all fitted together !). The pipe on there now is 120mm ( it does say so). They appear to sell a mix of 120mm and 125mm stuff and it is not always clear what the actual size is.
Incidentally, I thought I'd check the size of the grille I have had in the bathroom ceiling for the last 5 years (it also came from TLC). It was 120mm !
Anyway, I now have on order (from fastlec) two 125mm elbows and a 120mm to
125mm adapter.
Simon.