Hi Fikira,
Your razor was definitely made by George Smith, elected Master Cutler by the Cutlers Guild in 1749. His company was in Peacroft and was called 'George Smith and Sons' and the makers mark was a cross over the word 'Smith; as shown on your razor. It seems that Thomas must have been one of his sons and used the same mark.
Bailey's Northern Directory list George as 'razor cutler, penknife cutler, cutlery maker, surgical instrument maker'.
From Robert Leaders book:
Attachment 199423
Note the reference to great grandson Albert Smith, son of George Smith. In 1813 Albert became clerk to Benjamin Burbeary, a Kings Council at Law in the Chancery. His father accompanied him - Reverend George Smith, and the document was witnessed by Thomas Smith, a coincidence, as he appears to be a legal clerk or commissioner of oaths. Reverend George Smith was the Curate of Eccleshall, Sheffield 1804 - 1817. He died in 1817 at the age of 53.
Attachment 199424
So it appears that George Smith, cutler was father George Smith, reverend. The article says he had many sons, and at least two of these (George Smith & SONS) took up the trade and worked with or for him.
So, a lot of words that merely confirm the relationship (taking consideration of your own research) and a narrowing of the date.
Regards,
Neil