Clutch Slur and in at Elms

[cps]

Hello,
bit of advise and help needed. So my CSL is in at Elms. I have a warranty. I have clutch slur. We did a road test. They have updated software which I paid for. Clutch slur still present.

They have said that I need to pay for them to drop the gear box down ( £645) and if it need a new clutch pay etc. Fair if I have worn parts, but I'm just a bit concerned this might not fix the slur, and where this might end a paid " guessing. I've read the warranty book about what is covered etc. I have read the post from NZm3 on the GT1, although when I mentioned this they said "hard to interpret clutch where from readouts.

Does this seem reasonable to pay for the box drop and should I ask anything specific in proceeding in your experienced group view.

Service has been very pleasant so far there, nice courtesy car etc

thanks

Chris