The park and ride scheme seems to me to be unsustainable. There is plenty of parking within Leamington town centre. There will be no dedicated buses - I can not believe that many people will check normal bus times to ensure they arrive at the park and ride in time to catch one. Park and ride schemes appear to take time to establish themselves and my understanding is that not many outside of major cities succeed. There are better sites further away from Milverton - the roundabout of the A46 and A452 would ensure that those coming into Leamington, Kenilworth, Coventry and Warwick University, have the choice to use a park and ride.
More concrete usually means more flooding. Something we are all seeing and experiencing more of. Why add to the issue when there are other ways to ensure the housing quota is met.
The Railway station would be impractical to build. The station at Milverton was closed not that many years ago probably due to lack of use. I have not seen any research as to whether a station is even viable.