Dear Sir / Madam,
I spent a year doing data entry for Hachette UK, a London publishing house, and can guarantee an incredibly high degree of accuracy. I have equal faith in my research abilities, and can't imagine anybody better suited for completing this task for you.
Please let me know how long you expect this to take and then I can revise my bid for you; currently it is just an estimate based on the little information you have provided.
Thank you for considering my bid.
Yours faithfully,
David Bernhard