IHT and CGT help required

My IHT question is how to reduce the value of an estate to below the nil rate band when the main constituent of that estate is a London home.

The CGT question is how to negate CGT on the sale of my only house which I have lived in on and off for only a few years out of the 27 years that I have owned it.


The backround to the IHT problem is this: With recent house price rises in London ,my mothers home in now probably worth around £ 700-720 k. This was jointly owned by my mother and father. When my father passed away we put his share of the house(which he had left to his children) into a Nil Rate Band Discretionary trust (£250k in 2003) . The value of the home has increased since then and if my mother were to pass away , her share of the house would be more than her nil rate band inheritance tax allowance (fixed at 320k by the coalition govt.). As a rough calculation we would be liable for £100k inheritance tax. Say £720000 value of property - £300000 (value of the amount in the nil rate band trust ie. £250000 adjusted for inflation today) = £420000 £420000 minus the nil rate band allowance of £320000 = £100000
So the question is:
Is there any way to lessen the amount of inheritance tax we would have to pay. For example by my mother taking out some kind of loan which was repayable at the time of her death, to bring the value of her estate down. (Not necessarily equity release because of the high interest rates charged by companies offering those products and also due to the fact that they would have a charge on the house.)? I know that she could just give the house to me and my sibling and would need to survive 7 years , but we want the house to remain in her name till her passing. This is now a problem because London house prices have started to move up and it seems they will continue to rise making our situation worse in the coming years.


The background to the CGT question is
If somebody had bought a house 28 years ago and lived in it for a very short time (less than a few years) ; the rest of the time the house having had tenants ; is there any way to completely avoid paying capital gains tax by either living in the property or by using offshore companies or engineerin
It was bought in 1986 for around 60k and today would be worth around 350k.It remains my only home. Due to personal circumstances I have lived in it for only a few years on and off.
I have seen calculations on the internet about lettings relief / ppr relief and annual exemptions . I have attempted to work out my own CGT from these examples and it is very high. Even at 18% as a lower rate tax payer.