That's the one. Wreckless Eric was the other act. Costello, inimicably, did a set of almost entirely new songs (from This Year's Model) which was disappointing (but how wonderful it would be to go back in time and see that set again). It was Nick Lowe rather than Dave Edmunds, but I seem to...
I saw him twice during the Stiff tour of 77 (Top Rank and Drury Lane). Captivating.
I do recall (from an article in the NME or Observer, which were regular reads for me back in the day) he could be extraordinarily unpleasant, however, and that rather put me off him.