The reason there has been no "yes or no" reply is that, without sight of all of the paperwork from both sides, it is impossible to tell.
If the OP disputes the valuation he is perfectly at liberty to get his own. He is also free to refuse any offer of a secured loan if his proposal doesn't cater for the use of such a device.
None of us KNOW the relationship between valuer, loan company and IP (nor, it seems, does the OP). So we cannot give a definitive answer to a nebulous question.
As for "some posters being rather defensive", they gave their opinions and were rebuked -- so, yes, they are entitled to defend their responses.
If the OP wishes to take action he can complain to his IP's regulators via the Government Gateway and read up about the process here:
https://www.gov.uk/complain-about-insol ... actitioner
Regulators cannot overturn an IP's actions, if they were taken correctly, they can, however, hit the IP where it hurts in the event of malpractice and order fines (sometimes quite substantial).
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014