4 year PhD programmes in the UK are relatively new and usually involve a lecture course in the first year combined with short stints in a number of research labs before the student is asked to select a research topic. Although it is possible that some of these programmes would accept self funded students, we are not aware of any offering a mix of 3 years funded one year self financed. Don't worry too much, it's quite unlikely. As you have access to your computer send an email asking the university to clarify the funding arrangements for your PhD - they will not think any worse of you for doing so.