They are likely to be the same George W Blake, although yours first came over in 1904. They could have married in the USA, of course, even though they may have come over on the same ship. There is no evidence of a George William Blake marrying a Mary E in the UK (except a couple in Yorkshire who stayed there).
In case you didn't have the 1881 entry, here it is:
1881
Model Lodging Houses, 6 High St, Lambeth
George Blake, 33, cabman, b Lambeth
Elisbeth Blake, wife, 32, City of London
Elisbeth A Blake, dau, 14, b Lambeth
George W Blake, son, 11, b Lambeth
Benjamin J Blake, son, 8, b Lambeth
Arthur A Blake, son, 6, b Lambeth
William H Blake, son, 4, b Middlesex? Perhaps this is 'Uncle Bill'
Thomas H Blake, son, 2, b Lambeth
Albert E Blake, son, 1, b Lambeth
Once you have looked through all this, and are convinced they are your family, let us know whether you need any help with earlier generations.
Richard