I'm currently in the process of replacing my head gasket on my dual fuel 1.6 16v 2001 Astra and need two parts but my technical knowledge is limited on the names of these bits!

Can anyone identify please what the following are called?

First bit is an elbow joint which looks to be attached to what I think is the thermostat housing:

Close up of broken elbow thing:

Second is a gasket on what I think is the rear coolant entry point:

(Spot the piston into which the coolant got!)

If anyone knows the name of the elbow (or a good enough description to be able to order the part) and/or knows the name of the bit for which I need the gasket, I would be muchos appreciative!

PS: Never ever ever try to change a head gasket on a 16v Dual Fuel astra.... Vauxhall dealership turned their noses up at the job (hence I'm having a go!) which should have told me something about the complexity of it!!