Answer
(Fatwa: 1775/1671=D/1429)
(1) Yes, you will have to give zakah again when the second year is over.
(2) It is mentioned in the Hadith: لازكاة في مال حتي يحول عليه الحول (اخرجه الترمذي)
The zakah is ordained in growing wealth; growth takes place round a year, so zakah is obligatory when one year is over. And when the second year begins after one year, there is new growth in it which will come under the ruling of new wealth. If there is no real growth but only the growing ability, then that much will suffice, such as gold or silver apparently have no real growth but have the growing ability in case they are invested in business. Therefore, there will be new zakah every new year, such as the time of salah comes daily then new salah is performed, it is not enough to offer salah once in life. It is narrated in the Hadith that the Prophet (صلي الله عليه وسلم) had taken zakah of tow years in advance from Hadhrat Abbas: استسلف من العباس زكاة سنتين (اخرجه البيهقي في السنن الكبري)
You should have written what and how the sect Ahl-e-Hadith proves it from the Holy Quran and Hadith.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband