I am a huge fan of Jack Russell terriers, and as I sit here in the sale room writing this article, I am being stared at by one of the favoured Parsons breed.

Not a live one, I hasten to add, but a model of almost life-size proportions mimicking the quizzical look of the old HMV logo.

Now, old advertising memorabilia is hugely sought after, but the key word here is old'. Resin replicas crop up all over the place and not just of advertising items.

For example, the Japanese typically dressed in a kimono with a belt around the middle, the buckle of which was a small pierced carving from wood or ivory known as a netsuke (pronounced net-ski).

These, having become popular, are also now reproduced in resin. How do you tell the difference? Well a sure-fire way - almost literally - is to heat a needle to a red hot temperature and then push it into the article in question. A real piece of ivory may result in a small hole while a resin copy will melt into a hot gooey globular mass.

One thing before you embark on such a test is to make sure you have the owner's permission, and if it is not forthcoming, you might just know the reason why!