Unless I had the same nightmare as you, I can assure you that you're bang on with that and it was their official website promoting it. I think it was 28 years, not 23, and I clearly remember those 2 whoppers Kirk and Tyrone out of Corrie with their mugs plastered on their website holding up cards with the number of years since we last won a trophy on them.
This club sponsored shit about our trophy drought went on for years over there as @Gary James pointed out on one of his Twitter posts the other week. I've no issue with the banner itself as that's just banter plus I always found it amusing how they put so much time and effort into taking the piss out of us, while at the same time claiming they didn't care about 'ikkle Citeh. No, it was their laughable double standards which came racing to the surface with all the wailing and gnashing of teeth that accompanied the unveiling of the Tevez poster - from both club and fans alike - that I'm calling the fuckers out on. Their club aided and abetted a campaign that lasted for fucking years, yet as soon as our club does one single thing in return the sad bastards can't take it and start lobbing that stupid fucking "small-time" phrase around.
Cheers mate for that, I've spent hours on google trying to find something with no success. Yes it does show the hypocrisy for that rancid club to officially take the piss after our club has helped them out in their hour of need on more than one occasion.
Pity they didn't replace the banner with a 43 year one, that would have been a double for Mancini.