The casting of the Hawk engine bell cleaned up really quite well; the main bell was made round / circular; the inside hollowed out previously but the "fuel" inlet ribbed section was difficult to work with; some of the ribs were missing in places, had air bubbles trapped in them but generally the ribbed section was not circular.
A replacement part was turned from model board; the ribs made a bit thicker and rounded off (to cast more easily later). The original casting had the ribbed section cut off with the new part fixed in place with some cyanoacrylate.

Three tools (in some old pots); 1 is the Hawk Main Engine Bell and the other 2 are for the 44" Eagle Transporter, the 3d printed masters for the passenger pod and walkway VTOLS.

For a mate of mine over in Canada; some simple styrene panels CNC cut so that he can build an interior for the Round2 22" Eagle Transporter Passenger Pod.

The parts made out of some scrap from the offcuts bin simply double sided taped over a test cut.

The finished parts below and the screen grab from the Catacombs showing what he is trying to make.

http://catacombs.space1999.net/main/cguide/umeagle.html

I have picked up an old kit; an A&B Space 1999 Hawk. This will be fun, but a distraction from the 44" Eagle. The Hawk is in scale with a 22" Eagle; I guess this will go in to CAD and be the basis for a big Hawk to go with my Eagle.
The original bell and spare were both pretty much a solid block open topped casting; I didn't want to leave it like that.
This is a nice bit of work (the original); I have done a bit of research though and found out the filming model engine bell was the cap or lid from a household product bottle or something.

My first attempt at weathering the big model. Not great and all ready wiped off / sprayed over. I didn't mind that it is a bit harsh and heavy; it looked good from distance. Feedback from the community at All Sections Alpha and Eagle Transporter Forum has not been bad but definitely not studio!

I will try again, no problem. I have purchased  an airbrush and compressor now; hoping for better results!