Never used Doublebase, it's not Diprobase is it? Have epaderm and its just like thick vaseline.
To be honest, much as I hoped they would work and my poor dd was slick and greasy till about 9 months, in the end it's only the steroids topically that do the trick.
Mind you we used Dentinox for her cradle cap with no success, then we just washed her hair with aqueas cream (still do) and if the scabs looked like they would lift I would gently lift them off, otherwise I would brush her head with a soft baby brush, gets the blood flowing. It took a long time but was gone at about 6 months.
Sorry to hear about the exzema, its so stressful. DD was covered till about 10 months, it is now under control, but what a stressful time for everyone. You try everything you can in the hope that something will work, it gets a little bit better, then a lot worse. I have to say the first 9 months were not fun, but now she is under control and the most gorgeous happy little toddler (14 months).
I would get your GP to refer you to a Dermatologist now, you could be waiting a while, or if you can afford it, go private. If you are in London and want a private consultant recommendation let me know. In the meantime keep him emoliated all the time, carry a little pot of it with you anc just keep him greased up.Keep his nails as short as you can. Cotton hats only. I use non-bio and no conditioner.
Another thing we have found really works is a bath only once a week or sometimes even longer. It gives her natural oils time to work themselves I think. Now we do sponge her down twice a day with aqueas cream and keep all the little folds clean, before she gets lubed up with steroid cream.
I remember looking at all the little babies with beautiful skin and feeling so sorry for my little dd.
I also was stopped in the street by people to give me advice on what works for them and while I appreciated it all. I noted it down and just tried the ones I knew I could persist with.
I hope some of this is useful