Update: so I heated a defrosted mouse up in some very hot water 45-50°C (113-122°F) so that it was giving a reading of nearer body temperature without risking denaturing and proteins. Grasped it by the scruff with the forceps and presented it to my female (Eva BTW) she seemed extremely interested. Placed the mouse on its back. She came right up and took it head first.
Previously I had been heating them using sort of tempid water (30°C 85°F)and dangling them, worked for the male (Joe). Really quite pleased that it worked. Thanks for the help.