..........Is there any way of trimming the stabiliser really "manually" ?
Good point, the old 707 had two dirty great 'coffee grinder' wheels on the sides of the central consol, so that the pilots could really 'manually' trim the stabiliser should it decide to do something one didn't want. Sometimes one had to relieve the airload on the stabiliser by pushing the nose in the opposite direction to that desired, then when the pressure was reduced cranking the handle like mad in the desired direction. In this context the pilots may have had to pull the nose up even further momentarily of course to operate this truly manual method.
There was also a pointer which moved along a scale, so that one could see what angle the stabiliser was at.
Course it's all computerised now, therefore far superior, so nothing can go wrong, go wrong, go wrong.