Hi Tony .... if you decide to get a copy of the original birth certificate you can either obtain one from the original Register Office where your birth was registered or, you can pay £9.25 and order one online from the General Register Office. Their website is https://www.gro.gov.uk/gro/content/c...es/default.asp and you will need to provide references for the latter which I'd be happy to look up for you (I'm into genealogy and do it all the time). The certificates take about a week to be received from the GRO, unless an express handling fee is paid, in which case it can be turned around in 24 hours.
If you need the references for an online application, send me a PM with the full name at registration plus month and year of birth.