Have had both on prescription - you get a massive tub but you will be suprised how quickly you get through it. You can buy it over the counter too but its quite expensive even for a smallish tube.
I think alypaly has more knowledge in this area but personally I prefer diprobase- I find it more 'greasy' than doublebase and so it works better for me. I don't think either smell particularly bad - they sort of smell of nothing, which can seem a bit wierd when you are used to fabulous smelling (but full of itchy perfume) stuff.
Glad your DDs skin is a bit better.
Have been wondering if something about wearing the sun suit started the problem which has now caused her skin to be ultra sensitive. If this is the case hopefully after a period of hydrocortisone cream, plus whatever emolent works best, plus avoiding typical irritants etc her skin may well begin to calm down and improve.
Not saying she is allergic to the sun suit itself but could be something linked to wearing it- maybe she got more sweaty (sweating can cause flare ups in some people), or maybe the suit made her skin more damp with sea / chlorinated water, or it could have made her skin quite warm over a long period......... Obviously sun suits are great things but am just wondering if it caused anything to happen to the skin that it was covering that might have made her flare up like this. Just a guess- hope you don't mind.