If I had to own a Colchester to use in anger I'd try to find one of the earlier round heads.
They are far better made and in a lot of ways designed better. The square head apron is a disaster waiting to happen and when it does expect to pay between £1500 and £2000 for the spare for the apron alone.
I'm told there are quiet head stocks on square heads but to be honest I have never seen one. You can't blame small clutches or straight cut gears as many lathes have similar, my TOS is one and believe me this get some serious work.
I have had it 18 years from new and given it works say 4 hours per day to make up for the time I'm on other machines this is serious work, it's 10 lifetimes for a home shop guy and it's still deadly accurate.
Also induction hardened bed ways are a joke. Everybody relates the hardening to what you get on vise jaws and tools. Forget it, by the virtue of being cast iron and not steel the most you will get is 23 -24 Rockwell which is what soft steel is to start with.
If they get harder than that you are faced with warping, cracking or even snapping off. So yes it is harder than standard cast iron but not that much. Have you noticed than no one mentions what Rockwell it is ? only that is is induction hardened.
Myfords even stopped it because they had that much trouble with it. Raglan's went the correct way with having detachable steel shears hardened and ground to about 55 Rockwell but all that does is wear the underside of the saddle which is just plain cast iron.