On May 13, 1983 I was granted a Leave to Remain in the UK for an indefinite period visa and since then I have maintained this status by not staying outside the UK for more than two years. During my last visit on July 29, 2018 the border force immigration officer stamped my passport with a Leave to enter for six months and not as a returning resident. I am planning to travel back to the UK next month. Do I need a visa or I can still enter the UK using my indefinite leave to remain status