Squeaky window

It wasn't but, it is now, which presumes a piece of grit, for example, might have got in the works. It actually happened on a frosty winter's (when else?) morning and has been the same since.

The YT video on removing the door panel seems quite complex but, perhaps more time consuming than anything else. But is it going to be necessary, please, to do this in order to get to the window mechanism and see what it presumably bearing on the glass?

Comments and/or suggests for resolving this issue, preferably if possible without removing door panel will be greatly appreciated.

Thanks in advance for any help.

Nigel