Hi masterboy123,
Its irrelevant if you signed the documents they can always be cancelled if you find that the cost is excessive and you cannot afford it if you are not covered.
I don't recommend the 'fingers crossed' approach and for your peace of mind
one phone call to VHI will ease this.
VHI confirm this also. They quite often have direct payment procedures in place too.
The stress of worrying about it in the meantime won't help your health.
It is not a big deal to get the code if it is required by VHI, I have done this many times by contacting the hospital or the secretary of the consultant looking after you.
Best of luck with your procedure.