Do you know a possible Church for the Bloomsbury Marriage?
As mentioned above, the marriage is likely to have been at the church of
St Giles in the Fields. That would explain why it has not been found online, because those registers are not available online for this date. There is a film at London Metropolitan Archives.
The only other Anglican church licensed for marriages in Bloomsbury registration district in 1841 was
St George Bloomsbury (registers are online via Ancestry).
But they may have married at a
nonconformist venue, or at the
Register Office, for which there is in any case
no online access.
So you probably need to order the marriage certificate, as recommended above.