Rob,
I'm using CMP L grade short link, 5/15' or 8mm.
I brought 34 metres/50kg in a drum [ from Whitworths 100950 ]
Attached to that,just in case, I have 30 metres of 12mm braided anchor rope [ whitworths 72211 ]
I have never needed to deploy the extra 30m of rope.
I also had an extra 100m of 10mm anchor rope under that but removed it only yesterday as just a waste of space!
My anchor is a CQR [genuine ? I don't know if it is] of about 15kg [35lbs]. No swivel, just a shackle to the chain.
I have only had it let go on 2 occasions, [very early on] both when I had done a 360 with tide around it, and I now suspect with not enough chain out.
I did not have any problems during my 7 month return trip to the Whitsundays. If I have room to swing I now let 30 metres out, every time!
In my stern locker I have a 10kg sand anchor with 3 metres of chain. I've another 30m of the 12mm braided rope [unattached] to deploy it.
I've only used this on a couple of occasions to line Seaka up in a large swell.
Hope that answers your question Rob.