No matter what the requirements you can pretty much guarantee that someone underling at the MoD is thinking how to hammer square peg (a) into round hole (b) driven purely by the mindset of 'cheap'.
That's what the myriad of Staff Officers at the MoD are supposed to do.....look at all possible options. However, they are only that.
Until they start throwing serious money at alternatives such as Rafale then I'm sorry, it's not even a possibility.
I'm with GreenKnight121 on this quite frankly. Why settle for less capability by switching the entire focus from 5th Gen to 4th Gen. 4.5 Gen is just a made up category with the express intention of making the F-18E/F, Typhoon and Rafale crowd feel slightly more special IMHO!