As I run a store, we have a policy actually its my courtesy policy, the purchase must equal 10 % of the value of the big bill or sorry we have no change, at 6 am in the morning some bright spark will come in with a 500p or 1000p note and buy 20p worth of phone load and expect change for his jeepney ride, it takes me 12 hours to build up enough change and by the middle of the next day it is gone. We lose customer when we don\'t have change but now most know I won\'t just change their money for them, so in some way its all my fault you guys are having problems. Its the snowball effect, when I stopped doing it, everyone else stopped doing it.
My advise go to a business that handles a lot of big transactions, the hardware store or the grocery, go to the customer service desk and ask if they could change a bill for you, you should have no problems.