That was a pain in the proverbial

Got the chimney collar installed - the usual 20 minute job taking all afternoon. The hole saw was the wrong size and as effective as a nail file.
In the end I had to drill around 50 holes around the circumference of the hole and jig saw the gaps out.
The holes for the bolts were also a
challenge as I burnt out my drill and 3 bits.
Also managed to cut through one of the lighting wires - but soon fixed with a connector.
It was getting dark as I bolted the collar on and sealed around it with silicone.
Hope it stays warm and dry tonight for the sealant to go off.
Jobs left to do:
Cut the flue to size.
Insulate around the collar inside and cut a square of heat resistant insulation and stainless steel to match the chimney rear insulation.
Bolt the stove down.
Seal the flue joints.