On 3 Jun, 10:13, Onetap wrote:

I've no sympathy for them; every first-year plumbing apprentice & half-
competent DIYer knows lead is banned.

Most commercial pipework specifications require the use of lead-free
solder ring fittings; these are marked to show it's lead-free solder,
e.g. a YP logo in the case of Yorkshire Potable fittings. That should
ensure the solder is lead-free.

I've seen a plumber 'topping-up' the YP solder ring fittings with
solder from a yellow (lead/tin) spool. Nothing is fool-proof, fools
are so ingenious.