Does sweet & sour sauce actually exist outside of western takeaways?
I got my taste for it in Singapore at the local choggie down the road where the locals used to go and eat.
For general info: The best Choggie I went to outside of SE Asia was in Roermond, just on the other side of the market square from the town centre.
In the UK find yourself a Chinatown area and watch on a sunday where the Chinese go for their family lunch. Those are the places.