To deal with BS - EN 1st. As a signatory to European standardisation, the United Kingdom has to withdraw any standard when a European Norm is published which covers the same topic, e.g. UT of welds. Many experts think the EN's are much weaker than the BS's which they replace, lower minimum quality levels.
ISOs and ENs can remain in parallel - there is no mandate to wothdraw the EN but the pressure is on to make as many ISO / ENs as possible identical but there is an enormous way to gor before this transpires.
So in general there is not too much unifromity betweeen ENs and UK BSs.
