In addition to db1234db1234's suggestion, try the following:

The independent hotel website (NOT ihg.com) sometimes gives you a hint as to the owning company in the footer, for example:
http://www.hiheathrow.co.uk/ or http://www.hiwembley.co.uk/

Have a look at some of IHG's top franchisees e.g. Interstate Hotels & Resorts or BDL Group. Some group hotels even have brochures in the lobby for their other IHG-branded properties.

Finally, the IHG Owner's Association has a publicly accessible 'Pay Dues' page which can give a bit of info about the registered owner of that hotel..
Use this to find the HOLIDEX code of the hotel in question: http://www.owners.org/Benefits/FindM...otelsReal.aspx
And enter that HOLIDEX code here to look at owner info: http://www.owners.org/FindAccount.aspx
Keep going through the pay dues pages (obviously don't enter any credit card details!) and as you go through you should at least find the name of the owner, and also their email address on the card details page.

Hope that helps.