Receivers and mortgagee should be reminded of the case Holohan v Friends Provident [1966]ir 1 which basically states that mortgagee and receivers must obtain the best price for properties that is reasonable available. You should write a registered letter to the receiver, who is your agent and ask for the sale price of the property and the bids received, why the property was not put up for sale by private treaty, whether the property was a portfolio sale etc.
If the investment property is a residential investment property, you should consult the residential property price register and look for the prices achieved for similar properties in the location of your investment property (sold at around the same time as your property), take into account condition, number of bedrooms etc. If there is a large discrepancy between the receivers price and other prices achieved you may well have a case. The receiver has a responsibility to the borrower to act in good faith, take reasonable precautions and exercise due diligence when selling a property.