Does it matter if I have an odd tyre?

A recently purchased Fiesta has continental tyres except the near side front which is a goodyear with a similar tread pattern. Is this acceptable?

Is it illegal to have mixed tread patterns on the same axle?

I have read that you can be fined by the police for having mixed tread tyres fitted on the same axle. Is this true? My local Citroen dealer replaced one of my Cross Climate Michelin tyres with a Michelin...