She's doing ok if she can pay the rent on that place. I'm sure the taxman is getting his fair share...
Presume the details in the article are correct its through an agency she's had to verify income at least, probably provide a guarantor as well - so at least 60k a year must be going on her tax returns I'd say or them to accept. Shes probably not VAT registered when she should be, but still declaring more than most for a cash rich job like that.
Its just a shame they've run the story - consenting adults, sure Lampard didn't give to much of a shit before his name was dragged into this as long as his rents paid on time