Have you identified a supervisor? Potential project? I don't know how the DEL works but if it's like other research councils then funding will either be attached to a specific project for which you have to apply, or you come up with a proposal yourself, with the backing of a supervisor, and then apply for funding. They won't just give you funding to go and do a PhD in the same way that they did your MRes.
I guess having been funded before proves that you are fundable, and as long as you do well in the MRes might give you the edge over another candidate who hasn't been funded before.
Whatever the situation is, reconcile yourself to the fact that, unless you apply for a predefined funded PhD project, you might not be going straight from MRes into PhD. Funding councils make their decisions at specified times of the year, and applications take a while to put together, so you need to be prepared for some kind of time lag.