Late VAT fees - contractor

Hi

Ive being working as a contractor for a few years and started using a limited company a couple of years ago. I recently got a letter from Sherrif office looking for unpaid VAT, along with fees + interest. It was a very large amount and Im somewhat taken aback. I have being somewhat naive up to this point in thinking my accountants would be on top of this. Im using a large accountancy company popular with contractors. It looks like they changed process at some point last year, and I didnt properly read an automated email sent to me asking me to approve a VAT filing. Its my fault ultimately, and an expensive lesson to be on top of these things.

Im curious if I had gone with a smaller accountancy practise would they of likely picked up the phone and warned me about this? Or would similar things happen regardles?

Cheers