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You would have to (or be sensible to) have a survey before even bidding so very likely to lose the cost of at least one as you get outbid by developers/flippers. I think you'd be very, very lucky to save any significant money / get a bargain below market value that wouldn't have hidden, unexpected costs. Auction rooms are full of people doing it to make money with plenty of experience in buying that way - it's not for the faint-hearted.
You would be brave to do that