Hi --- Inheritance tax is not an issue as long as her total estate falls below £300k, at the date of death so forget that if that's the case.
Capital gains tax will be due if she transfers the house to your ownership as you don't live there, but this would only become due when you sell it in the future. It would be payable on the price difference between what you acquire it at and the price you sell it for in the future. i.e. worth £100k now = sold for £150k in three years then = £50k would be liable for CGT upon sale which will be 18% after April 2008.
You are allowed at the moment £9200 CGT allowance in a tax year, before you have to pay any CGT so you could deduct this from the £50k gain, although the above sum is only an example.