It's great that you've got it going, Malcolm. The datasheet talks about 5K as sort of a maximum value, optimal for a single device but there are all sorts of conditions where you'd want it smaller. If you are running in parasitic mode with a long lead, if you have multiple 1-wire devices on the same bus, if you are running at lower voltages (say 3.3 V), you will find you need to lower that value. The datasheet has an example circuit for effectively lowering the value to near zero while the device takes it's reading. Bottom line is that there isn't a single best value.
So if you have 1 device on the bus, running at 5V, not in parasitic mode, 4.7K is perfect. If you have a different configuration, and you have troubles, try lowering the resistor to 2.2 K. Larger values like 10 K are unlikely to ever work, as you discovered.
There's a lot of discussion online about these devices including a couple application notes that talk about these exceptions.