Hello Folks,
Looking at my earthing (TN-S) I see a 6mm2 earth wire come from the
service head thingy
to my CU, then another green 6mm2 earth wire exits the CU and dives below
the floorboards to clamp onto my lead water pipe.
Since I now have gas and central heating pipes which appear
unbonded ( except by secondary means ) I decided to bond them to the main
earth, but I have some questions that Googling didn't clear up.

(1) Can I use 6mm2 earth cable for the short runs from my gas and CH pipes
to the main earthing point?

(2) I have some BS951 clamps which are a puzzle to me: I thought that one
threaded the strap through the clamp and tightened the screw, which would
tighten up the clamp on the pipe, but what I
took to be the clamp section ( it has the earth terminal attached to it )
does not move at all when the screw is tightened ( yes I backed the locknut
off ). Two metal dimples in the main clamp section prevent it from
tightening on the pipe. I figured I was wrong about how they worked so just
pulled the strap tight and screwed the screw down to lock it, but it is well
nigh impossible to get the strap tight in this way - the clamp rotates and
so can't be giving a good connection. What am I doing wrong?

(3) I believe that it is unnecessary to run an earth cable to my bathroom
( which has no bonding at all ), and that merely bonding all the exposed
metal bits to each other with 4mm or protected 2.5mm cable is OK??????

(4) I understand that suplementary bonding is not required in anyother
situation, i.e. kitchens and toilets????

(5) I cannot fit all the new earth cables into the earthing block in my CU -
only one terminal is still available, so I bought a metal busblock (?) which
I intend to mount exposed on the board, alongside the CU, and I will bring
the main service head earth into that and then take all other earths out of
that block, i.e. to the CU, to the CH pipes, to the gas pipe etc.

thanks for any answers or observations,

Andy.