Halifax Building society

I appreciate a survey when you buy a home with a mortgage but the Halifax insisted on a survey to value the house after it had been on the market for 18 months “to prove it was worth more than the £55k offer on the table” which it isn’t . Personally I think the £55k is quite generous considering, but the Halifax surveyor insisted it was worth more without even seeing it . They are struggling to pay a token amount slightly less than interest only but this could have been solved months ago . The Halifax are yet to respond to my official complaint and I hate what they are doing to a young family making their lives a misery .

This practice is universal. If you take out a mortgage the building society or bank will arrange their own survey which you pay for. They will not usually share it with you. Sometimes you can use the same surveyor to do your survey, which will then be cheaper because there is less work involved.
It seems a unfair to refuse a negative equity sale if the balance of the loan was being paid off, probably work an ombudsman application. Can they carry on paying the interest on the loan? A bank or Building Society will generally accept interest only until a sale goes through.

I'm sorry to hear about your DD's trouble with the Halifax, but I'm not surprised. We were with them when we had our first house. The service (or not) that they provided then was appalling. I'm very disappointed to hear that they haven't improved.
Just sympathising really, I can't offer any help.

Thank you for your response janemar I haven't contacted the financial ombudsman yet as I believe you have to allow 8 weeks for a full response to an official complaint (very happy to learn otherwise though) . I am however preparing a case ready to do so. Just flicking through various websites it seems that the Halifax has an appalling customer service record.

Have you contacted the financial ombudsman? I have had dealings with them and found them to be very helpful and quick to respond. You can start with an informal chat or email to see if you have a case.