£1500 - how long are you going for? 2 years??

Don't change it here, the best rates are out there. However, i would be very hesitant to change such a large amount of money in one go. Some money changers (i.e. in Kuta) like to pull a fast one on tourists unused to handling such big value currency notes (£1 = IDR17,500 ish).

If I was you, I would deposit it in a Nationwide Account which doesn't charge you to withdraw overseas, and use the numerous cash machines. And possible a couple of hundred quid as emergency back up.

Work on £50 a day and in reality its probably £30 for two, and its only that expensive in you like to have a drink.

Or you're on your honeymoon, which we are....

Certainly change your money when you get there. You may want to think about changing a small amount of money when you arrive at the airport for tips until you get yourselves organised.
The Kodak money changers in the street are generally honest with a good reputation and won't try and rip you off but still be careful and be the LAST person the touch the money.
Also, always get clean notes in good condition other wise you'll have difficulty using them. Another thing is when you change money if they say they only have small notes then go to another money changer who has larger notes... they are harder to count (all them 000's) and you'll end up with a wad that won't fit in you're wallet.
We was in Bali a couple of months ago and my husband came back with no money and was chuckling... he said the money changer said "No money... is raining"
We budget on $100 Au a day... don't know what that is in pounds but I think 50 a day would be ample unless you're going 5* and/or eating in the hotel every meal, they are expensive and bung 21% tax on.
Cheers Geri

Well- if its your honeymoon, make sure you go to the silverware shops and use up all that excess money you'll have