To all I hope you have a better new year this year rather than the one we just had. I also want to apologise for the use of the word electricians and all quote. Was below the belt. As there are some very clever electricians in this forum.
I was in my mind looking at a blue pipe and from my memory of that blue pipe was a question where the OP said is it worth bonding.
My ADS is - If you can, make sure you can on site if the plumber is there, get it done. If not make a note.
As for bonding. I still make sure that a property has the correct figures at distance example a bathroom bath point. Worst I have seen is 0.14ohms and added a CPC to the metal bath. I thought that was reasonable. You will die still in the bath as unfortunately you need a faster trip time than RCD and RCDO can give at present.
I believe under 6ms, but tech changes all the time. Lets hope.