Motorway etiquette

Just before I get back to work (I am in the office, but not on the clock at the moment), I thought I would seek your opinions on something that happened this morning.

The exit slip road from M1 J24 becomes the entry slip road for J23A when you are going southbound. I need to leave at J23A to get onto the A42 to get to work. As the road was fairly busy, I had to pull into the middle lane to let traffic out at J24. As J23A became ever closer, I was still stuck in the middle lane, as the traffic was too close for me to pull in and prepare to leave the motorway.

J23A was now only half a mile away, and I was still in the middle lane. But, by now, a lorry on the inside lane had pulled over, a stream of people had pulled into said inside lane, and were proceeding to overtake me on the inside. I had my indicator on, making it fairly clear that I wanted to pull in, but a steady stream of three or four cars steadfastly refused to let me in. In the end I kind of had to push my way in, which I hate doing, partly as it is bad manners, and partly because I don't want to have a crash!

Could I have handled this differently? As far as I can tell, I tried to pull over as soon as it was safe, but by then these cars had filled the gap. But even though they were on the inside lane, they wouldn't let me in. I am sure this is not the way things are supposed to work.

For the record, the cars were two BMWs and a Passat (along with Mondeos and the occasional Mercedes, these are the "usual suspects" when it comes to motorway "issues"). It was another Passat that I had to "push" in front of.

Any views would be appreciated. If you think I was handling it wrong, then do say - I need to know for the future!