Radiator in bedroom never worked. Been trying to fix it. Took it off wall last week, rinsed it out. Pipe going in hot, suggestion it might be TRV. Today. Drained system, took TRV off, put new TRV on. Refilled system. Bled radiators. Still cold. But also leaking!! From picture. Black circle part is hot, part under red circle not hot. I thought the leak was coming from Green circle area, but on draining the system again, I could hear air from orange nut on blue area. Should i replace red and orange nuts? If so, how do i get them off the radiator parts. Any ideas? If the green area is leaking, can I fix it? Got British gas homecare, but thats a week for an appointment. I have no hot water or heating anywhere else until i fix this.