Tax relief on Nursing Home in the UK

My aunt in the U.K. may have to go into a nursing home shortly. She lives in sheltered accommodation and has no children or husband. She has a disability pension and very little savings. Unfortunately she is suffering from dementia which came on very suddenly and so cannot look after herself. I am her only niece and would like to help towards the cost of the nursing home. Can I claim tax relief if the nursing home is outside the country?

I'm not an expert in this area but from reading the Revenue website:

The nursing home must be on the Revenue's approved list of nursing homes

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Assuming that the home IS on the above list, you should be entitled to claim tax relief on the portion of Nursing Home fees which you pay which are NOT reimbursed by anyone, including your aunt

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Also, as far as I can see, the tax relief is at your high rate of tax and not the 20% rate, as with most (all?) other medical expenses.