OK all done (I think - I guess I'll find out in an hour or so!).
Got the ScrewFix one and didn't find any vaseline around the house (!!) but there was a bit of fresh-ish gloop (suspect silicone grease) left on the thread and around from where the plumber just fitted the previous one - so I just smeared that around a bit. I guess I need to check for leaks when it starts to warm up??
Anyway thanks to everyone - particularly Seco - that helped me out with this, really appreciate it.
Got the ScrewFix one and didn't find any vaseline around the house (!!) but there was a bit of fresh-ish gloop (suspect silicone grease) left on the thread and around from where the plumber just fitted the previous one - so I just smeared that around a bit. I guess I need to check for leaks when it starts to warm up??
Anyway thanks to everyone - particularly Seco - that helped me out with this, really appreciate it.