Firstly....'One Nimrod has also been taken out of service and stripped down to check for mechanical problems'......
Use of the word 'has' implies that it has actually happened. To the best of my knowledge it remains an intention. I asked the question before on 12th July, and (as with most of my questions) got no reply. But has the aircraft actually left Kinloss yet, or is it just 'going to' at some point!
As to the point regarding the R1, I believe that the reason it won't be kept going to 2025 is on the grounds of cost. When the MR2 goes, if the R1 was left to soldier on, then the cost of maintaining certain type specific items would be prohitbitive for a fleet of 3....