Gosh, does that mean that if this is the right link, Poppidirk will now have fabulous dreams? (-;
to come back to s. o.The secret method: google for keywords (here: 'get back' plus his nick) plus site:.leo.org, click on the cached version, note the title (since the URL no longer works), go back to LEO and search for keywords in the title.
I think since only yesterday the LEO software is now even converting old links if you paste them into a thread -- and maybe even showing the title of the thread, though that seems less universally successful so far. Let's see if the same link would have worked without {a href="etc.}:
new-style numbered link (idThread=1840&idForum=4):
Siehe auch: to come back to s. o.old-style link by date (&group=forum004_general&file=20060511102125):
http://forum.leo.org/cgi-bin/dict/forum.cgi?a...Don't know if it will ever be possible to access old-style links from outside LEO, but at least after a transition period, the new ones should replace them in the search engine caches.
To get back to the actual question, I agree that 'get back to' is the normal way to say this. 'Check back with' is fine for shorter intervals; 'get back with' is heard a lot in the US but does sound much sloppier to my ears as well, and 'come back' just sounds wrong to me. So I would say
Sorry to be / Sorry I'm just now getting back to you
Sorry to be / have been so slow to get back to you
Sorry it took / it's taken me so long to get back to you
etc.