English menu and notices in a cafe

One of my friends has been running a cafe in Tokyo. He wanna have an English menu and notices and asked me to translate them. Could you check if it is good and let me know when something isn't nice.

"Please return your cups, glasses and trays here. Thank you" (This notice will be placed over the dish return)

"Larger size for extra 100 yen"

"50 yen off your takeaway orders"

"Opening Hours
Tue- Fri | 9.00am – 8.00pm (last call 7.30pm)
Sat, Sun | 11.00am – 8.00pm (last call 7.30pm)
Closed every Monday "

"Here is the key to the toilet"

The issue is that I have no idea how to announce that there is a discount for customers who have their drink without having a seat (There is a tall table for customers who prefer to have a cup of coffee or espresso in a short time. Customer can enjoy coffee beside the cafe counter as well).

Thank you in advance.