Replying to a university offer I have applied to study at a UK university for a taught masters starting in 2017 September. I also obtained an unconditional offer from one university. They have mentioned to reply to the offer within two weeks. But, I would like to wait till I hear from other universities. Can I request from this university to give me more time to make the decision as I have applied for 2017 course and there's a lot of time till 2017 September?. 

I also intend to apply for the Commonwealth scholarship for Master's and PhD study for developing commonwealth country citizens. In the scholarship guidelines it is mentioned that 


  You must take the necessary steps to secure admission to your
  preferred universities in advance of your scholarship application.


Does this mean I have to accept the offer at a university to apply to the commonwealth scholarship or I should only have been offered a place at a university before I apply. Because in the commonwealth application I can state up to 3 universities. But I can only accept 1 offer right? So, I think I only have to have an offer from university. Is this correct?  

Also, is there a way I can delay accepting the offer until I get a decision from the commonwealth scheme.  I believe the decisions in commonwealth sholarships are made in around 2017 April. So can I delay that long (From 2016 August to 2017 April) to make my decision on the offer? Do I have to pay tuition fees to accept the offer?    

I would be extremely grateful if someone with experience regarding these can give me some advice on these issues.
It is not wrong to request for more time to make your decision. But, as @Nate pointed out, you may not always be granted what you request for. 

If you do not receive the time you ask for, then it is a gamble you may choose to make or decide to play it safe. Many go through this sort of situation. 

There is however another option. If you can't postpone your decision for the first institution, you could try preponing the your offer result of the other institution. Give a kind request to know your status of the application to the other institution to be in a position to decide earlier. This is also just a request, however it is still worth a try.