when subletting / shortletting privately

I just have a question related to the subject's topic...
I know I'm new here  so I go assuming that I don't know the norms, other than what I've learned through very helpful and friendly people here in this forum...

I recently rented a place for two weeks (actually thirteen nights) and we ran into two (not so) small and minor misunderstandings from the person renting it out to us.  (other than that they were very helpful and nice).  So I just wanted to hear some second opinion(s).
I'm going to round the numbers a bit so it's easier...
Supposedly, we rented out the place for two weeks (1/06-14/06) and pre-paid the two weeks rent and a two-week deposit.  So, assume rent was 250/wk, we paid 1000.  All utilities/costs included/inclusive.
So at the end, I though I would be getting 500 deposit back, but the sublandlord said the rent was for half a month and not for two weeks, so it was not 250*2, but 250*4.33/2, so I'd be getting 460 back and not 500.   I understand the 4.33 conversion for full months, but it didnt make sense pro-rating the exact two weeks to half a month, but I told him it was fine as I gave him the benefit of the doubt... then he took another few days (up to a week I guess), and right before making pmt back, he said something like "oh, and council tax for the month is 96 so prorated it would be 43, so you're only getting back 413... but since I cannot deposit coins I will deposit 410... I owe you a drink"
So to that I had to tell him that if this was the case he should have told me something when I sent him the pre-payment, like telling me I did not pay in full or something about any other extra charges, to avoid any misunderstandings,  because even though he may be right, it just didnt 'seem' right...   so to that he actually agreed and said it was his bad and he would waive the council tax cost but that it was a totally separate cost from the utilities... which I agree and understand, but it's nice to know what's coming beforehand    was I wrong to say that?  I thought at least I had to ask and explain my concern/confusion...
At least it's good so we learn to be more careful and clear next time.  Thankfully this was a small and non-issue, but confusing...

was I wrong to say that?  I thought at least I had to ask and explain my concern/confusion...
At least it's good so we learn to be more careful and clear next time.  Thankfully this was a small and non-issue, but confusing...

I haven't rented/been a landlord in the UK, but here in the US, I would think your actions/assumptions were completely correct.

I have a roommate who is moving out this month, and as she came by today, we had this conversation...
her: "So what about the $100 for the part of the month I'm not living here?"
me: "What about it?  You're entitled to live here until June 30, if you leave early, that's your business"
her: "Well, every other place I've lived has prorated the last month's rent"
me: "Sorry, but we didn't agree to that beforehand"

[Other minor details include the fact that she hasn't even paid June rent, and I requested that she move out because she violated the terms of the lease, so I'm not really inclined to do her any favors.]

Anyway, long story short is that I would act based on whatever was agreed to/signed on at the start of the sublet, and address other amounts/issues as they come up, as you've done.

Side note, I do think it's weird that a 2-week sublet magically turns into a "half month" one, especially since technically 14 days is less than 1/2 of the 30 days of June.

It wasn't wrong for you to raise your concern but I am surprised that you were learning the cost at the back end rather than the front.  I would never agree to something if I didn't know the full rate in the first instance.