UKC

I am interested in the section of the limestone way from Thorpe to Matlock and, having looked at the OS explorer map I can see it clearly marked. I have also got the impression from online info that it is clearly signposted with markers along the way. In previous occasion, I have managed to see the trace of long distance walks in google maps satellite view but in this occasion i can't discern any evidence of a well throdden path in the area that is marked on OS and other maps. I can see other paths as the pennine way etc...but no sign of this one.

Any idea why and is really there a well marked path to follow?

This is particularly useful for things like that https://wtp2.appspot.com/wheresthepath.htm so may be of use to you. 

Can't help with your question specifically though. 

Did it a few years ago Rocester to Monyash (But didn't do the matlock spur). Signage was not 100% reliable as the Limestone Way but always on clear footpaths and with any reasonable map reading or gps its easy peasy.

Obv can't speak for anything happening in  the last few years or for the bonsall? to matlock spur

Yes, I will expect to be able to find the way, seen that I have got the map, although I am surprised that I can't see the path from a satellite view !