I'd a lot of the answers come close to your definitive answer. I'd say do your research on the ADR website or speak with a BPA registered company possibly.
TREM cards don't exist anymore.
What do you carry as you say "cat1"? Do you mean class 1?
Your enquiry is covered by UK Domestic Regulations.
The UK DGR regs say you can transport 50KG of 1.1G to 1.3G or 500KG of 1.4G before you enter ADR.
ADR requires Rectangular orange plates front and rear of vehicle 400mm x 300mm wide with a 15mm black border and Plackards of 250mm each edge wide placed in diagonal axis(diamond shaped) on each side of vehicle and on rear. Under no circumstance should the signs be placed inside of vehicle whilst tansporting!
Your class 1 goods should also be in suitably marked and labeled in UN approved packagings,displaying UN Number, proper shipping name, 100mm Class 1 labels showing division and compatibility group and securely sealed, also undamaged!
If you follow full ADR you must be ADR certificated and carry your original with you whilst transporting subject to regulations.
info at
Carriage of Dangerous Goods Manual ? Regulatory environment
Introduction to the carriage of dangerous goods
SITPRO Trading Advice: Dangerous Goods Note Completion Guide
You could also make an enquiry with Chemfreight.
Just a few pointers
Hope this helps
Regards
Graham