Okay...more information on this situation...
My mechanic re-checked the bowden cable and there was no difference.
One thing he also tried was disconnecting the bowden cable entirely and driving like that...that didn't make a difference either. It was shifting really late even with the cable disconnected!
He checked if the bowden cable is sticking or anything and it's not. He's worried that it might be something wrong with the transmission and says it might have to be opened up and the valves and stuff checked.
Before I get him to do this, is there anything else I should try? I have a feeling this is going to get expensive if he starts doing work on the transmission.
Thank you for all your help,