Thanks, ***** ***** this is illegal without good reason.
There are several options as you have said:
1) A caution - but you have to ADMIT the offence
2) Court - that is for the Police to decide. The Court do NOT decide whether to prosecute, but the Police do.
In reality unless you have a reasonable excuse then you are likely to get a blot on your DBS check. This is because knife crime is taken very seriously indeed.
I realise this is not at the extreme end but if you have no convictions you may be offered a caution.
This will show on your DBS check for a limited time. But some offences are also filtered after a period of time and wont show.
As the offence took place in Herts then yes you have to travel there, that is normal procedure. If you have a good excuse you may be ok - I note you say you use it for food preparation, but unless you have containers of food etc with you, its unlikely they would accept this excuse.
I am sorry if this is not necessarily the answer you want and certainly not the one I want to give you, but I have a duty to be honest.
Can I clarify anything for you about this today please?