How does one report the illegel use of a CE mark?

Your second post provides much clearer information.

Unfortunately the CE mark you apply is based upon your tests and declaration against the various standards. If your competitor has similar testing then the application of the CE mark in itself is not illegal as your company does not own the European Standard - this is the common method allowing free trade of goods where everyone certifies against the same standard (think you might be getting confused with BS KiteMark and similar where a reference number unique to the manufacturer is applied).

Trade mark infingement is a different matter and solely down to who can afford the litigation costs - if you spent the money making the registration it is worth defending as any faulty goods could be incorrectly attributed to yourself.

You could independently purchase an offending item if readily available on the open market, have it tested and IF found wanting Trading Standards must then act upon any false claim to market.

Bit more information in your latest post - obviously these are not readily available on the market more a "bespoke" installation which makes purchase and test a non-starter.

This is probably why trading standards have backed away from involvement as it would be very costly to acquire and test such a product (bit different from popping to the shops and buying an electric drill at the local DIY).

Have you considered a mail shot to insurers, trade press and local fire brigades advising your product is being copied and "may not comply with relevant supply legislation for product confirmation / genuine supply contact.."

Any customer purchasing a supposed compliant product could sue the actual supplier for breach of contract (Goods not as described, not fit for purpose..) and dont forget the Miss-Representation of Goods Act 1967 (from what you describe their claims are fraudulent if they are applying your company name)

Thanks again for your advice

The mailshot idea seemes a bit extream but as they ignoor our corispondance that may be my only option

I would take action against the person or company and directors of the company importing and distributing them. If your objective is to stop them rather than get damages I would use the petty claims court, which I think will allows you to claim up to £5000 and cost about £35 to submit a claim.

You need to do some detective work and name both the company and directors or person, and find their addresses. Winning the claim will be a bonus but the objective is to put enough pressure on them to stop what they are doing.

One tactic to keep the pressure on is to put in claim after claim for every incident they have supplied counterfeits of your product until they stop. By actually naming an individual increases the pressure but if a company is involved it is likely they can easily get that part of the claim dismissed.

If it goes to a hearing just turn up and argue your case yourself. If they do not turn up you are likely to get the judgement in your favour and you can then instruct bailiffs if they do not pay.