vaxhall corsa 1989 1389cc?

Hello,
For the work undertaken, is it still under their warranty?

Is the oil topped up?

They may of fitted a warpped head, or you may have a head gasket leak. The injector rail may not have been fitted properly or it may be blocked. I would of checked and replaced the oil pump and water pump. I would also check the radiator to see there is no air in the pipes or leaks.
It sounds as if the system is over heating.
Book in in asap and have them re check all the above. failling that, check the oil gadge.
All the very best.

Dommy Dom, Passion of Triumph motorcycle service.
April 2009