For our USA members, Dyna-Tech was Raleigh UK's version of Technium. It was similar but not identical, using different lugs.

I see that Ebay UK currently has a Dyna-Tech 525 in a 23" frame for a £199 BIN. If it it fits, I strongly suspect that the OP would be financially ahead by buying it and selling off the Camapgnolo Mirage components, as opposed to repairing the current frame.