Hi Shona,
once you have the names and dates of the people you are starting with, my first port of call would be the BMD Indexes at
www.freebmd.org.uk.
FreeBMD is an ongoing project, the aim of which is to transcribe the Civil Registration index of births, marriages and deaths for England and Wales, and as such the whole index has not yet been transcribed.
It is a good starting point, and of course it is free!
In the interests of fairness, the Ancestry website
www.ancestry.co.uk has a completely free search/view of images of the Birth, Marriage and Deaths indexes for England and Wales from 1837 to 1983 and also transcribed indexes from 1984 to 2004. Use the index details to order Birth, Marriage and Death certificates.
Once you have the reference for each certificate (To order certificates, the website I personally use is
www.gro.gov.uk, the website of the General Register Office. Certificates generally take about 10 days to arrive.
Best of luck with your research!
Hawkeye.