There's no legal requirement attached to using .org or .org.uk domain names. They're 'intended' for non-profit-making organizations, but available for general use. I would say it just needs to be obvious on your website that you're a business. And obviously:

"If you are based in the UK and run a business web site to sell or promote your products or services then make sure that you are meeting your legal obligations.

Note that as long as your business is physically based in the UK then UK laws will usually apply - even if your web site is hosted in another country."
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If it's brokenless, don't suffix it...