I think you have slightly misunderstood the situation. Full civil registration information for England and Wales is only available via purchasing the certificate in question. This has always been the case and it is unlikely to change in our lifetimes.
The Family Records Centre (the successor to St Catherine's House and, before that, Somerset House) housed the paper versions of the GRO *Index*, bound in wonderful, huge ledgers. Until relatively recently, anyone wanting to locate the registration of a particular event had to wade through these ledgers in person to find the GRO reference required to order the certificate.
The GRO Index is now available digitally in a number of ways. The on-going volunteer project FreeBMD (www.freebmd.org.uk
) has transcribed it to the middle of the 20th century. It is also available via Ancestry, FindmyPast and other online suppliers of genealogical data.
If you wish to order a certificate but cannot be certain which index entry is the right one, the GRO can do a check for you if you order the certificate online via www.gro.gov.uk
. Make sure that you select "no" when asked whether you have the GRO reference. You need to enter a year of birth, but the GRO will search that year and one either side. You will then be taken to a form which allows you to enter information such as forenames of parents, mother's maiden name etc. If there is a match, the certificate will be issued to you, if not, your payment will be refunded in full. There is no extra charge for this service, just the standard £9.25 including postage, but it does take a bit longer (15 days rather than 4).
Hope this helps