We've taken two formula fed babies to DLP on 5 occassions. We tend to take formula in powder and then boil the tap water in the bottles. There are some excellent sterilising bags you can fill and hang up in the bathroom at night to treat the bottles using cold water (they are sold at Mothercare). The baby centres are excellent. You can buy formula from the babycare centres, but it is a different brand and could upset your baby's tummy.
As for kettles and bottle warmers, all the hotels have them, just ask at the counter. Also, to warm the bottles in the parks, the counter services will give you hot water in a couple of large cups (just explain and show them the bottle, and the cast are great).
And for changing, although the baby centres are excellent, almost all the toilets (including the men's) have a changing mat area.
Have a great time.