I was at a NAPIT seminar this evening, a chap from the IET was also there to enlighten us and this matter was discussed.
It would appear in the eyes of NAPIT and the IET that the regulation stating manufacturers instructions must be followed does in fact require the use of a torque driver on not only your cable terminations but the checking of factory terminations as well. I m pretty sure that not all manufacturers instructions include torque settings, for example the Cheaper brands like CPN and the God awful CHINT boards (I do plan on verifying this).
As is often the case this is a regulation written for an ideal word and IMO leaves the electrician exposed to potential prosecution. But maybe I'm just being synical.
As it happens I do own a torque driver and use it whenever I discover manufacturers indicated settings, for example the Schneider (Merlin Gerin) breakers and boards have the NM requirement printed on them. I feel that if things are moving in the direction of electricians being required to install to precise torque settings all manufacturers should display there torque settings on the breakers themselves not buried in a leaflet or in some cases listed on a website.