Migrate 3 wordpress sites to Fasthosts, maintain sites with SEO

Migrate 3 sites from web developer to Fasthosts, ensure all is working correctly.
Migrate email addresses, ensure all is working correctly
Assess websites and perform any neccessary upgrades, improvments
Maintain and monitor websites, performing neccessary tasks/improvements and providing
Provide basic SEO for websites

These websites were recently down/hacked under current developer. My ranking on one has gone from 1st/2nd to non existent. I really want this restored to normal.