Never do ebay after a few Jack Daniels!

[IanS1]

This might be a good place to start, http://www.spindlesas.co.uk/ I bought my Elte spindle here, (sorry to say this but it has an ER25 collet), Trevor was good to deal with.
They do tool changers as well; http://www.eltesrl.com/ look uder 'Products' Tab

Cheers for that Eddy. He's only just up the road from me, will give him a call when I'm ready for the spindle.

[Ger21]

I doubt that your machine has enough power to really take advantage of a 16mm tool, let alone a 20mm tool. I'd try to re-sell them and buy smaller tooling.
On our $100K machine, we cut with 1/2" bits at 20-25 meters/min with no issues. I have a 5/8 (16mm) compression spiral in the ATC for jobs that need deep cuts, but I'm afraid to push it really hard as the cutting forces are incredibly high.