Hi Nuneatonman, Thanks for your sound advice. That's what's good about this site people here understand what you are going through. I am pleased to say the sleep unit were good, checked the
machine, hot plate and came to the conclusion after reading the card,my mask was leaking quite a bit.When I had my annual review last September, they didn't have the Fisher Paykall 431 in stock so gave me what I wanted but it had been used on demonstration days so although it had been sterilized wasn't brand new. I am a fan of this mask after trying lots of different ones, although the valve connecting to the mask and tube is noisier than previous ones in the past. Fortunately I had a spare older valve and swapped it over. Had a good 5 1/2 hours sleep last night without waking up and was soon able to drift off again. Feel human again to-day. Yippee!!