register with trade body.....answer plz

[roop]

Hi everyone,
i need expert advice from all of you . my question is that is it necessary to register with trade body . i got tier 1 visa last year . the nature of my business is graphic design. till now i did not register with any trade body . when i applied for visa the home office did not ask any thing about it . my company register with company house, hm revenue, i clear all my account every year. If it is necessary to register can you guys please help me to find any trade body for graphic design.anyone who applied for extension share their experience and what doc required
thanks