I don't think any future announcement regarding possible Indian routes will involve Spicejet.
Spicejet have recently made an announcement that for now any thoughts of long haul expansion to Europe is of the cards and the airline will concentrate on their core markets and expansion going east rather than west.
There was an article that covered the announcement on ch.avation a couple of weeks ago.
Vistara on the other hand still intend on long haul expansion to Europe which more than likely will include the United Kingdom.