Second lock? I don't even use a 'first' lock !!

I rely on the alarm / imobilizer.
I never lock the steering because those locks are worse than useless. A clout with a hammer or well placed boot will, and has, dispatched them!!
I really must start using the disc lock though. I have just bought a tool roll for the front and, until I can sort a holder out, it will no doubt fit in there.