>>>i'm not sure that solicitor fees are taken into account when calculating iht, just the value of the estate
Sorry, you can't deduct the solicitor's fees from the value of the estate when calculating IHT.
Quote: "You shouldn't include professional fees you pay for when dealing with the estate - things like solicitor's and estate agent's fees. You can't deduct these from the value of the estate but you may be able to claim them back from the estate later"
Source:
http://www.hmrc.gov.uk/inheritancetax/how-to-value-estate/debts.htm
IHT can be complex but the basic principles are straightforward enough. Simply add up the value of everything your father owned (such as the balance of his bank account, the value of stocks and shares and the value of the house) and then deduct any debts that he left (such as unpaid taxes, credit card bills, etc) together with the cost of his funeral. That's the value of his estate for IHT purposes. (OK, I've simplified things quite a lot and assumed that he didn't make any
major gifts during the 7 years prior to his death but that's basically what you need to do).
Then deduct his tax-free allowance. That could be just £325,000 but if his wife died before him, leaving everything she owned to him, he will also get her allowance as well, so that would be £650,000 to deduct from the value of the estate. Then (assuming that your father didn't leave at least 10% of his estate to charity, when a lower tax rate would apply) HMRC will want 40% of whatever is left over.
So if your father's assets other than the house (after all his debts have been settled) didn't exceed £155,000 and he'd inherited his wife's £325,000 allowance there will be no IHT to pay.
For all the fine details of IHT, see here:
http://www.hmrc.gov.uk/inheritancetax/index.htm