This is part of the problem, those in favour of Brexit have convinced themselves that it means a simple form here and there to enable movement of goods, people or services as in pre Brexit days. In your industry it may we'll be simple.
But let me give you an example of a food exporter. If they export any product of animal origin they have to get a health certificate signed by either an official vet or a qualified food inspector from the local authority (the latter can only sign if the consignment is fish). If the local authority can't do it, then the exporter needs to find an official veterinary officer, and there are not many of those around. If and when an exporter finds a vet, the process for issuing a health certificate is complicated. Where there are several forms each has to be stamped and signed in a way that satisfies the EU rules, the vet has to then watch the consignment being loaded onto the lorry and certify each step. All this while the LA or the vet charge the exporter an hourly rate which is upwards of £75. So costs and time soon rack up ( for a process that was previously very simple and no additional costs). If the exporter wants to send perishable goods across then it is often not worth it. I find some brexiteers willfully blind to these additional burdens.
Now, in the future a better trade deal might make the export process less onerous. But at the moment it is not always just a case of completing a "simple" form. I think that is why we have seen a major drop in exports between the UK and the EU, previously our largest export market.