Much advice is at hand for sellers on how to make the most of a viewing-from styling their house to ensuring their kitchen smells of freshly baked bread -but little is available for buyers. The idea seems to be that you simply look round a house and, if you like it, outbid everyone else and the job is done. The problem is, failing at buyer’s etiquette can lose you the vendor’s goodwill-and the property.

One of my relatives recently had two offers on her home, but rejected the higher bid. She had brought her own children up in that house and preferred to sell it to ‘a nice family with three young children’ rather than the single middle-aged man whose pockets were deeper, but whose motives for wanting a five-bedroom house were unclear.

It may sound strange but your children can often prove to be an asset at a viewing. Philip Harvey, at Property Vision, advises buyers to ‘take well-behaved children to view a treasured family home, as vendors like the thought of another family growing up in it’.

However, you need to be sure of their behaviour-Knight Frank’s Nigel Mitchell saw a potential sale disappear when ‘a child started jumping on a bed and our client asked the buyers to leave’. Charlie Wells at Prime Purchase has found that ‘unruly child-ren and dogs are the easiest way for an owner to be put off’.

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Some viewers also forget the basic courtesies of turning up on time, introducing themselves, offering to take off their shoes and thanking the vendors when they leave. Mr Harvey tells of showing ‘an old rectory to a London-based client. He was running late, screeched to a halt in the driveway in his Ferrari, dashed straight past the “gardener”, viewed the property in a flash and dashed straight past him again. The “gardener” was the owner and was so offended that he refused to sell to him.’

James Wyatt of Barton Wyatt even ‘had a viewer no-show after numerous rounds of booking, cancelling and re-booking’. As a result, ‘the vendor instructed me not to rebook as he would not sell to a “mannerless cretin”‘. ‘Owners also find it difficult listening to people discussing how to improve a property,’ warns Mr Wells. A vendor once refused to sell to someone who’d brought an architect along to the first viewing to discuss what they would rip out of the house.

Of course, if the seller isn’t going round with you, you need not be so guarded-but watch out. Strutt & Parker’s Will Watson was showing a house and ‘while upstairs, talked through a few negatives with the buyer. When we got downstairs, the owner was frosty with the buyer-finally, we realised that we’d been in one of the children’s rooms and the baby monitor had been left on.’

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