Right, it's obviously good news that he advertises with the option of a refund.
It sound as if he will be taken to have sold in the course of his business, in effect being a dealer of trailers (or similar). This is good for two reasons.
Under the Consumber Protetion (Distance Selling) REgulations 2000, if you purchase as a consumer over the internet you will get a coolingoff period of 7 days from the date you were able to examine the trailer. You should either write or email to him (faxing or sending by Royal Mail Next Day delivery) citing the legislation and the right to refund advertised by him and state that you are exercising your right to terminate the agreement and obtain a full refund.
The as a consumer contract it will also have the benefit of the terms implied by the Sale of Goods Act 1979.This means that the trailer must have been of a satisfactory quality., if it is not it will be a breach of contract under which you could request repair and a refund if the repairs are not adequate. There is also a term which states that the goods must correspond with the description given by the seller, so you would be entitled to have the misdescribed defects remedied.
In all likihoods you will not have to rely on the implied terms by the SGA1979 and will be able to obtain a refund under the distance selling regs, but if he disputes the applicabaility of the distance selling regs this is another avenue of recourse for you.
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