Turns out my calculations were wrong,  so over £200 of left over parts that need a new home. All the metal parts as shown in picture are included. Originally from ductstore.co.uk but their returns policy is not hugely generous.

The tubes are:

4 of 1m lengths

2 of 1.5m lengths

1 of 3m BUT it's stuck in the loft so I'll probably need to cut it to get it out... you can specify where you want the cut.

Also various bends with seals as shown.

Collection only.