I could access any Archive in the UK, provided I took recent printed proof of who I was with my address on the same AND my Passport (or a photo Driving Licence for those who hold one).
If you come from France or elsewhere, you'll also need evidence of your temporary address of where you are staying, as well as your usual home address.
The British Library and others have suffered losses, items removed or cut out and managed to prosecute one offender, so you'll need to prove who you are.
Many of our ancestors names might be missing in C of E and records, due to being Nonconformist, Roman Catholic or refusing to register, until it became Law.
The only archive which were awkward with me in my 30 years and said I could not visit as they had no facilities for visitors and would not photograph a Register (even for payment) was a Roman Catholic Diocesan Archive in Yorkshire, who admitted to holding a late 18th Century Register (not online), that I wanted to see.
Subscription websites only have a fraction of the records that exist hidden away in Archives.
Ancestors names appear in many old Manorial records, Land Owner, Probate, Property and other records and are not always listed in the usual run of the mill type records, you find online.
Not everyone in England and Wales was C of E, or was baptised C of E!
When E & W Civil Registration started in 1837, some still didn't Register Births.
You had to Civil Register a Death from 1837, to get a Certificate of Burial, to pass to your Undertaker. I have an 1845 example of one of these.
Mark