Wilfred you may regard some of the replies as flippant but your on a uk forum. For the vast majority providing water is not an issue nor should it’s source (cow pat) be an issue. You in no way need to attract bees to any water, if you provide the right conditions they will find it!! Having spent a decent amount of time in Melbourne and it can get hot. Most Aussies I know get cold down there. I’d imagine there are only a limited number of times you’d even need to think about it. The main reason I’d think any source was needed was to prevent a nuisance in neighbouring swimming pools. To sum up bees like warm water(probably not an issue for you)a sunny spot is good. The crapper the source the more stinky or dubious the more likely the bees are to prefer it
Don’t over complicate the whole issue or overly worry there are quite literally thousands of other aspects of beekeeping that you should be improving on before this should be on the radar. Stick a damp shallow peat tray under a dripping tap/irrigation in a sunny spot job done. It really is as simple as that! Ian