So information on the internet is wrong! This is news? Discogs is just one of many websites attempting to catalogue music recordings. Most of them are fairly rubbish, and rely either on unreliable bots or unreliable humans to supply the data, which is often sparse or simply wrong. Discogs do at least say they to want to achieve accuracy, and ask their users to add information and correct errors. Some other sites don't seem very interested - I've been trying on and off for about 8 years to get All Music Guide to change the genre of my band's album from "Pop/Rock" to "Folk" but despite repeated submissions through the corrections page nothing is done.

The mistakes you complain about seem to arise from a deliberate choice Discogs have made to credit the main artist when specific information about a composer is not available. I think that's a highly questionable approach and it would be preferable to leave it blank, but they do ask their users to correct errors. This does seem to be a fairly new feature, and a very superficial glance at the user forums suggests you are not the only one to point out the flaws in this approach. If you are having difficulty correcting the error then I suggest you focus your complaints on that, rather than simply complaining it is wrong, which I'm afraid is endemic to the internet, especially when what was a hobby site grows out of control.

Overview of the Tracks feature

Google will only turn up search results, if those are inaccurate it's hardly google's fault. However I searched for '"Home to Inverness" composer' and the first result was Stewart Ross with the Tryst Players which correctly shows the composer as Stewart Ross. Joss Esplin would have been third, but has been pushed down the rankings by two links to this thread (so I suppose it has achieved one of your objectives).

I do wonder what purpose these sites think they serve, as they are so often riddled with errors. I agree that anyone researching the source of a piece of music should treat all these sites with considerable caution, and where possible go to the official databases held by the performing rights organisations.