You must be sure that the company meets all three criteria.
How do you check company registration?
You should check the register at Companies House, using the free Webcheck service at companieshouse.gov.uk. You should look at the full register entry for the company.
How do you check if the a company is carrying on business in the UK?
You must be satisfied that the company is carrying on business in the UK. The business can be non-profit-making.
Even if you have direct personal knowledge of the company, you should check the Companies House register to see if:
the company is in liquidation, dormant, or about to be struck off
the company’s accounts and annual return are overdue
A company may still be carrying on business if it is in liquidation, dormant or late in filing documents, but you should make extra checks to satisfy yourself that this is the case.
For any company, you should consider looking at:
the company’s website
relevant trade, telephone directories or reputable websites
the latest accounts filed at Companies House
If you are still not sure if the company is carrying on business in the UK, you should ask for written confirmation of its business activities from the company’s directors.