It is difficult to get accepted with a third class degree. You are very unlikely to qualify for any UK research council funding. However your distinction in your MSc will help. Demand for software engineers in industry is high, as are the wages offered which means that demand for PhDs is less than in some other subjects. You need to look for projects funded by other bodies or for a job as a research assistant.
As we always recommend talk to your tutors from your MSc course. They know the subject area and the relevant research groups. If anybody knows what your realistic chances are they will.