There can be a consumer contract only if a consumer has entered into a contract with a party who pursues commercial or professional activities. The application of the special rules in Articles 15 to 17 BR I is justified solely where there is an imbalance between the positions of the parties such as to require that steps be taken to reduce or to eliminate it in order to protect the weaker party. This is the case only when the other party is engaged in a commercial or professional activity. Therefore, so as to avoid doubts of interpretation, Article 15, paragraph 1, under (c), BR I, which applies to most consumer contracts, expressly states that Section 4 is applicable only when the opposite party, with whom the consumer enters into the contract, is ‘a person who pursues commercial or professional activities’.
My interpretation: You, an individual, signed a marketing contract with an Estate Agent, albeit a Business Transfer Agent. You signed it as an individual as your business is a separate entity with its own bank account. You, personally, are the 'weaker party' because the Estate Agent is engaged in a commercial or business activity.
If you contact National Debtline, a free service, they may tell you that you need to contact Business Debtline. But you were not purchasing a service, or the product of that service (a few advertisements online and/or tiny adverts in a newspaper) that you would use in your 'usual trade or profession' . By signing the 'agreement' you were contracting OUTSIDE your usual trade, it was a 'one-off' transaction. If a genuine buyer had actually followed through, you personally would have received the money from the sale and would need to pay Capital Gains Tax on any profit over the current limit (£11,000 in 2016). The business would not have to pay the tax as the monies cannot go into the business as that is sold to A N Other and you don't want that person to get the profit!
The views expressed above are supported by some judges but not by others - it seems to vary according to a particular Judge's knowledge and experience. Contact the website NATIONAL DEBTLINE even though you may not consider you have a 'debt'.