Okay you need a cream to act as a barrier to stop the wee getting to it - but you clearly also need to let the air get to it...
The air is more important - so to prevent the wee staying there too long get nursery to change her every 1.5-2hrs and ONLY wipe if she's soiled.
They also need to be pretty hot off the mark if she's poo'd...
Are you using paper liners at nursery? If so stop using them for now... We couldn't use them with Isabelle at all...
How many days is she at nursery - obviously they can't do nappy off time in the same way as at home...
Don't wipe her when she's wee'd as wiping off the cream and wiping in general aggravates. (sorry if I'm repeating myself!)
Use either redbush tea or cammomile tea to clean her with - don't use wetwipes at all....
Keep washing nappies at 60...
Definately avoid all citrus and probably tomato too as it's quite acidic and has a knock-on effect on wee.
Also avoid kiwis as they're quite sharp too...
A GREAT way of helping heal is to soak a fleece liner in cold cammomile tea and place it in a night nappy so you're putting the wet liner against her skin - this is great moist wound healing and this was FABULOUS for Isabelle's skin when she had dreadful rashes.
Get rid of ALL microfibre in nappies just don't use it - I use bamboo instead these days...
Angel Baby Bottom Balm is the BEST nappy rash cream I have found and we swear by it and believe it is magic
It's not too thick and you can pop it on at every change if needed...
Personally I'd avoid sudocream and other zinc-based nappy rash creams as that could be irritating it further...
I didn't find silver liners helped us at all really - they were thin and polyester based
Silk liners are supposed to be the bees knees though... (but I think you have to hand-wash them!)