Fix hacking / cloaking attack on wordpress site, improve security

Hello

My site is currently subject to some kind of 'cloaking' attack – our google results are full of spammy links, somehow there are new 301 redirects on many of our pages. I have identified there is a difference of 28kb between the version of the page we server to users/browsers and the page that Google sees, which means there is some code running on our site somewhere / somehow

I am looking to resolve this very quickly as it is a live issue on a major website. Happy to pay for a serious expert who genuinely knows what they are doing.

Once we have discussed then I'm happy to provide all necessary details to my site and be on hand to help resolve it.

Many thanks
James