Inheritance tax paid wrong amount "right of residence" vs "life interest"

My mother gifted the family home to myself about three years ago. At the time we instructed our tax advisor to pay the tax bill based on a “right of residence” of the property to be held by my mother from that point further. This tax bill was correctly paid at the time.

We recently changed solicitor and our new solicitor has informed me that he believes what actually occurred according to the documents from the time was that mother has a “life interest” on the property rather than a “right of residence”. The land registry seems to state that while I am "full owner", it also states that she has “the rights and privileges specified in instrument number XXX in favour of <mothers name> during her lifetime”. He is going to investigate it further and come back to me with confirmation tomorrow.

What I want to know is if we paid the tax on the basis of a right of residency but in fact the housing documentation (deeds etc) state it’s a life interest she has, what are the implications of this?

Essentially:

1. Would the tax bill have been different?

2. Will this be easy to change? What I mean by this is not can I change the amount of tax paid, but can I keep that tax bill in place and change it from "life interest" to "right of residence" without affecting the tax?

3. If we change it, will my mother’s right of residency be considered to have begun three years ago? Or from todays date? (I mention this because the HSE fair deal scheme takes a “life interest” into account but not a “right of residence” .)

Don't worry, sounds like a right of residence,not a life interest.

If she had retained a life interest any gift tax you paid would have been less, not more.

But I don't think that is the case.

Thank you for your reply, very helpful.
What makes you think that is the case? Is it the wording of the land registry?

When it says "specified in instrument number XXX" is that referring to a different document?

The way it is registered sounds like a right of residence. A life interest would be registered in a different way. if pre 09, the life tenant would show as the owner, if post 09, a trustee would hold for the life tenant but there would be an inhibition on the folio. The instrument is a copy of the land registry file which effected the registration. It will have a copy of the original deed of transfer which will recite what happened.

Thank you so much. I think you are right. We have reviewed correspondence from the time of the transaction and it all suggests it was a right of residence. We are just waiting on the final clarification from the solicitor.