Thanks for all your messages - will try to answer everyone.
Beebar tend to agree with you about nasties in steroidal creams, hence why I have avoided using them so far. I have been healing myself from inside in for a long time. I take probiotics (very high dose ones), I avoid dairy (only eat goats cheese occasionally) and drink Oatly. I am mediterranean in origin and have a good diet. Very little meat, loads of veg and fruit every day. We don't eat any packaged food at all, always cooked from fresh. If in France, we occasionally succumb to the amazing cheeses and some wine and brioche. It's a holiday ffs! The rest of the time in UK, those food are banned for me. I also eat low salt. How you conclude that my diet is shocking is a mystery to me, and to others 
Turquoisecat I am only a little overweight, thankfully and on the road to getter fitter. I'm not aware of any conventional health issues, other than this blasted itch. I agree with you that diet plays a part in managing some skin conditions, but haven't yet found a link between any foods I eat and my itch, sadly.
Peaceof I vacuum a lot, with a good cleaner. I'm not obsessive about cleaning, but I try to dust every week. I always wash bedding at 60 degrees and also found a laundry liquid that kills fungus and bacteria, just in case.
We air every day and only have hard floors. The itch doesn't change one bit if I go anywhere else (apart form that April 2014 occasion - but then we went back this year and the itch was worse, if anything). I have been a little stressed with a bad family problem to do with my mother last year that has merged into this year. Am dealing with it though and moving on, but you're right that stress can't help.
MrsM can't believe the term at Guys also got it wrong
- it doesn't exactly inspire confidence! So much depends on the GP you get on the day, but will try again. I agree that if it's eczema, that also needs to be looked at from the inside out, not just by throwing topical stuff at it. That's why i ma having acupuncture and looking at lifestyle and diet changes beyond the ones I have made already.
BIWI thanks for your reply - I had diflucan over the counter. No different. Was on the pill in my 20s, pill-free since 2005 and no intention of going back on it, as I don't like the idea of my body being interfered with by artificial hormones, at my age.
I have had very few antibiotics in my life and have been taking very potent probiotics for about 3 years. I also drink apple cider vinegar diluted i warm water, occasionally.
Interesting what you say about your symptoms. I have had actual thrush about 5 times in my life. I never have thrush discharge normally (sorry for TMI) nor any other classic symptom of thrush.
I have had a slightly lengthy gynae history, in that I was TTC for 3 years, until recently, and had 8 miscarriages in that time. MC due to old eggs. All other blood test and exams normal. Have made my peace with that, but am knackered and have been trying to kickstart to a newer, more energetic me. I used to be very get-up-and-go, but the MC took it out of me. That's also why I gained weight, because i was tired for so long, itching at night, knackered from MC and not moving enough. I was a size 10 when my DD was born in 2008, but once the itch started in 2009, weight slowly crept on.