Travelling to Tunisia with load over Brexit decision Time

I have picked up a film job in Tunisia from end of Jane to April 2019 which I have to transport my camera tracking vehicle to in a 2001 Merc Atego grid box body. I run on a Restricted O License here in the UK and normally am only operating here. Done a few foreign trips over the years but not recently so trying to get a handle on the documentation I require. The goods in the truck are my own and belong to the business and technically are my tools for the job I have been hired to do.
As I understand I need all the usual vehicle documents, my customs documents for the equipment in the truck and additional permits in the way of a Bilateral Permit for Tunisia, a European Community License and a ECMT in case we get a no deal Brexit. My concern is that the ECMT is only available to trucks with a Euro 5 specification and therefore registered after Sept 2015 and my vehicle is Euro 3 registered in 2001. Does that mean that nothing younger than 2015 will be abel to transit the Continent after the Brexit decision in March.
Not sure if that is all the permits needed and not sure what other options I have available to me so would appreciate any advice if its available out there. Many thanks

There is a post in the owner drivers section about ECMT’s should be helpful enough.

Many thanks for that Mazzer2. I’ll have a look at that section now.

I am working my way through the paperwork for the above trip and am coming across various references for Attestation Documents. I dont work as a truck driver for a living so I tend to have a variety of gaps on my tacho cards as sometimes the truck isn’t driven for weeks because I am doing other things. I depart for the above job on the 19th Jan but prior to this the truck will have only been driven by me 3 times probably and all of those really short trips so the previous 28 days shows quite a few gaps.
Is this document still required and if so where do I get a copy of one that I can use as a template that will take a variety of dates and activities that are not to do with driving the truck? Given the fines levied I want to make sure I cover all bases on this if I can. Many thanks for your thoughts…