I think, in general, that it is secure.
I use NatWest, Halifax, Intelligent Finance and ING online services and, touch wood, no problems so far.
The problem with Cahoot was not so much a lack of security but a lack of proper testing of the new software before releasing it on an unsuspecting public.
In any event, banks do guarantee that the customer will not lose any money due to errors by the bank.
If you're unhappy; take your money away from Cahoot and put it with another bank.
By the way, I do NOT work for a bank!