Latest update on my mini odyssey since changing the cassette...
Wasn't able to shift much by the end of my last ride, and found I couldn't shift at all after trying to index the gears. Spotted fraying occurring on the rear gearing cable under the downtube so decided to have the cable out for a look...
Had the bike on a stand and dismantled the rear gearing cable and when the cable came out of the 105 shifter it looked like this...
Saw the cable had dismantled itself in and around the internals of the shifter so took it to the only place open...
Halfords....
The guy essentially took it all apart and managed to get out the jammed cable and the stopper thingy at the end of what was left of the cable...
No wonder I was struggling to shift...
Thanks to
@themosquitoking for his help today!