The phrase "jobless recovery" was new to me. At first I thought it was just a synonym for "return to high unemployment", but it turns out that a jobless recovery is something more specific. Wikipedia defines it as:
Recovery from a recession, where "recovery" is defined as growth in gross domestic product (GDP), which does not produce strong growth in employment
Wikipedia also points out that the phrase is "used by economists, especially in the United States" - I'm not sure whether it has entered common use in British English (although here's a Times Online article from February that uses it prominently).
Anyway, perhaps the Conservative Party article should have clarified what Theresa May meant by "jobless recovery". I certainly didn't know.