Hi there
(1) Try 1837online.com.
(2) 1837online.com covers Civil Registration Records from 1837 onwards, not just for 1837.
(3) Loads of reasons why he might not have been on the census in 1901 (he avoided it, was living under an assumed name, had gone abroad, etc, etc)
(4) "joseph walter sheppard born lambeth 1d 361 august 1891" - you can apply to the Public Record Officer for a copy birth certificate. Log on to
www.col.statistics.gov.uk to order online. When asked if you have the GRO reference, choose Yes and enter Volume 1d, page 361, 3rd quarter 1891 - the certificate will cost £7.00, and you will be given an estimated despatch date. I've found that if you know the GRO ref, your certificate arrives sooner than the despatch date.
Good luck!