If you are doing an MRes then it increases your chances as funding is often 2.1 or 2.2+masters minimum. Usually though it is the universities who make the offers, not the funding bodies directly if you were going through that route(BBSRC or EPSRC most likely in your case). If you're doing well on your MRes then it will be in your favour. Also be prepared to explain why you got a 2.2 but that you turned it around. But don't let it put you off, go for it !