"Long wait for pre-booked bed"

I went for an investigation, requiring an overnight stay on PIU. On the day ward the investigation was completed, and I was got out of bed (they needed space for more patients coming through), dressed and dumped in a chair by 11am. I had no pain relief even though biopsies had been taken internally making it painful to sit up. All I kept being offered by the nice staff who felt impotent was tea and biscuits. By 12.30 I asked when I would be moving onto the ward, as I was looking to lie down to relieve the discomfort. I was told PIU had told them not to ring them before 3pm (even though it was known I was having the investigation early in the day) regarding the bed. I waited until 3.15pm, and asked the nurses the situation, and was told the bed manager was in a meeting which they weren't sure what time she would be free to ask when the bed would be ready. They then informed me a patient in the same situation the previous weeks had had to wait until 8.30pm for their bed! After having sat in pain for four hours, with a further potential six hour wait ahead of me I self-discharged against advice. There was no way I could bear to sit in that chair any longer. The only transport I could get home (hospital car was booked for next day and the office was closed so I couldn't change it by this time) was a taxi. Given I live an hours drive from the hospital it cost me £50 to escape. The nurses were concerned that I might become ill overnight, and asked me to go to A&E immediately. I pointed out I was an hour away so not able just to 'drop in' as they suggested should I feel ill. I had to take a risk, going against medical advice because of the inhuman wait when they knew I was in pain and needed to lie down. I had to go home alone, with no help, and no option to return save by ambulance should I feel ill in the night because the ward did not have the bed which had been pre-booked available for over four hours. What's worse when the nurses called and informed them of my decision they didn't even apologise for the over four hour wait in pain I'd already endured.