I do not breed merle because quite simply the pattern has never existed in the history of the breed and it has also never been in the german spitz which is where poms came from.
The merle gene was introduced into the pomeranian breed by crossbreeding them to shelties.
Therefore merles are the result of crossbreeding and producing fake pedigrees.
I highly advise against buying a merle from the UK and certainly do not encourage the breeding of them. They are banned in the whole of europe for a very good reason. If you really must insist on having one i would only suggest buying from the usa from a breeder who is also showing and winning with them because they are the only people who have been working hard to produce good examples of the breed and i have to say there are some very good examples of them in the usa from the right breeders.
People who have them in the uk have done no research and have bought from dubious sellers with no or fake pedigrees and they are only in it for the money or they would not be breeding them.
No reputable breeder would ever breed a pattern or colour that was banned in there country for health and origin reasons.
You will be able to buy from the usa from a dedicated breeder for far less than they are charging in the uk so it is worth looking into importing from America if you really must have one.