From the July/August 1981-Midlands pictures.

25208 (front) and 25213 await departure with the 0800 Northampton - Morecambe MYSTEX at Nuneaton.

It took me a further 24 years from the date of this photograph to actually identify this train as people of board said it was going to Llandudno (which I believed at the time).  Eventually TRACTION published an article showing these two locos had been at Morecambe on this day.  Quite possibly the only Mystery Excursion I ever travelled on where I didn't know the ultimate destination in advance!