Our 18 month old cat is an absolute fiend at night. We haven't had a full night's sleep in months due to his behaviour. If we leave our bedroom door shut, he starts scratching on it at around 3am, building up to loud meowing, scuffling and then full on throwing himself against it. If we leave the door open, he comes in and bites our feet, scratches on the sheets, jumps up and walks on us, etc. He is relentless and will stay scratching and thumping at the door for up to an hour at a time, multiple times through the night. We've tried all the advice about active play for an hour or so before bed, followed by a specific signal that we are going to bed and it's time for him to settle down. He has the full run of downstairs and when he does sleep, it's on the couch. All his toys are in the living room, litter tray and dry food in the kitchen. He just seems incapable of entertaining himself throughout the night and wants to wake us up. He is mostly an indoor cat - due to our location in a built up area with drivers that see the speed limit as a minimum rather than a maximum, I never felt safe letting him roam. He has a Protectapet enclosure in the yard so goes outside, but not away from the house.
I feel absolutely broken by the lack of sleep and don't know what to do. Can anyone help please??