Hello, I'm Keith and happy to help you with your question.
I assume that you are a married couple. If so any estate on death over 325K is subject to IHT at a flat rate of 40%, but inter spousal bequests inflate the 325K by the amount of those bequests. On the demise of the survivor they also have a tax free element of 325K in their estate, but are also entitled to a further tax free addition of the unused 325K or part thereof of the earlier deceased partner's 325K making an exemption of 650K a possibility. In these circumstances it is normal for each party to make what is called 'mirror wills.' There will be no IHT due on the death of the first partner if their estate passes to the survivor.
Don't waste your 10K on questionable advice. Go and see your local solicitor to arrange a couple of competent wills to settle your respective estates on death. It should cost you under 500 quid. You know Benjamin Franklin was right, in life there are but two certainties, death and taxes and a simple will can abate the latter considerably. Can't do anything about the former, sorry!
I do hope I have pointed you in the right direction, your local high street solicitor.