You mean EFT trench-1 on user can't upgrade it to trench 2 or 3 level and same for trench 2?Sir, probably it will be Trench 1 and 2 which will be upgraded over the years. This is provided PAF does get them.
TFX is having some delays, fortunately one of the major issue regarding the engine has been solved. After the recent developments it is certain that more intent would be shown in TFX as Turkey is considering lowering the number of F-35's. How ever F-35 was to replace the F-4's and TFX was to replace the F-16's.
This could indicate some delay now but faster production which would benefit in regards to export. The target date would still be the same for the time being.
Now going to the J31, the delivery dates would be 2020-2021 because most of the research that is being done on J-20 is being incorporated on the J-31. There are some rumors that China might also procure the J-31 for the Western and Southern regions and keep the J-20 for Eastern regions.
J-20 is said to be available by 2019-2020.
Trench 1 still remains a Air Defence Fighter.
Upgrade it to trench 2 then it is a decent ground attack aircraft.
Trench 3 is going to be a true Multi Role fighter.
The MLU KIT is not available. Also there are issues with spares hence to keep RAF EFT serviceable 4 aircraft were scraped. Now after Brixit it looks even more difficult. It will be seen how the divorce goes...
IMO EU would still keep existing contracts & treaties,and the British Courts would continue to enforce the. However British Parliament would have her Supremacy once again and European Parliament would have a limited role of having various new agreements and treaties.