Hello Mondo!!
You have done a great job out of that old Revell Model
I like the paint job and don't worry about the flag, because it was only used when Departing/Arriving at port! The Bull of Scapa Flow looks great!!!!
I would like to advise you on three things (since you have done such a great job, if you want they will improve your work more) This is constructive critics!!
1 - The periscopes should be painted crome / silver, only the tips are painted with a grey paint;
2 - The cable forward of the Conning Tower has only one cable, not two - please check Martin's VII-C u-boat, he has a good close up of this area.
3 - On the floor plates and bulkheads and cutted areas, you should paint them red - like in the engine room compartment - it will give that professional look

Understand my points - I am only trying to make the model even better - no harm intended
Good work - and you still have more time for another one, RD Loteria

Please let me know about what I pointed out and about continuing aboard DDD

Skipper
EDIT: You also should have placed this post in the correct Campaign - you forgot to make any Group Association