Will this be enough on its own to dispute?
As a minor point of clarity, it's not an offence.
To be clear - the company you're representing is the registered keeper of the vehicle, with the V5C in their possession? If so, then yes, the notice being delivered outside the 14 day period should be sufficient.
I've included below the usual template for companies, assuming the notice doesn't wrongly claim to be able to hold the company liable under PoFA. Although if you could upload the NtK before submitting anything, that'd be preferable, as I personally don't like offering advice on a notice I haven't seen.
Dear Sirs,
We have received your Parking Charge Notice (Ref: ________) for vehicle registration mark ____ ___, in which you allege that the driver has incurred a parking charge. We note from your correspondence that you are not seeking to hold us liable as the registered keeper, under Schedule 4 of the Protection of Freedoms Act 2012 ("The Act"). You have chosen not to issue a Notice to Keeper in accordance with The Act, and it is now too late for you to do so.
As a body corporate, we cannot be the driver. There is no obligation for us to name the driver and we will not be doing so. We are therefore unable to help you further with this matter, and look forward to your confirmation that the charge has been cancelled. If you choose to decline this appeal, you must issue a POPLA code.
Yours,
[COMPANY NAME]