Nonsense......note the term "IMMEDIATELY entitled"
5 Doctors, dentists, and hospital treatment In the UK,
NHS emergency care and primary care provided by GPs is free for all. Secondary care and the provision of free NHS nonemergency hospital treatment is based on being ‘ordinarily resident’ in the UK. It is not affected by your nationality, whether you pay UK taxes or NI contributions or own a property, nor being registered with a GP or having an NHS number. If you are a UK national, you have automatic right of abode in the UK. If you have been living abroad, you pass the ordinarily resident test on resuming settled residence here and are immediately entitled to free NHS non-emergency hospital care
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https://www.ageuk.org.uk/globalassets/age-uk/documents/factsheets/fs25_returning_from_abroad_fcs.pdf