CM - as I understand it there is a level of international consensus to move from SWL to WLL.

LOLER (which mostly simply consolidated previous legislation e.g. Section 27 of the Factories Act 1961) refers to the safe working load but says in the guidance that sometimes different terminology may be applied.

Can't see this as being a particularly good reason to suddenly change all your documentation nor to remark lifting equipment to read WLL instead of SWL! - particularly if your operations are entirely within the British Isles.