Update: My doctor informed me today that, based on my urine sample, I definitely have a urinary infection. The only symptoms are this blasted night time incontinence. So the sample is off to the lab for them to identify the actual bacteria involved, then a short course of antibiotics should solve the problem. I am so hopeful that this nightmare might soon end! In the meantime I can report that the M&S Period knickers helped, but did not completely prevent stains. I had taken a photo of one stain and the doctor found that really useful as it gave an indication of the scale of the problem. I will report how I get on with the meds - but wanted to say that everyone should tell their GP if they get any new incontinence - even if they have none of the other classic symptoms of a UTI.