MissSueDenim did make some very valuable points. Op you are very defensive - wanting to suggest you bear little responsibility for what has happened. What exactly do you want people on here to say - that there is a magic thing you can do to change what has happened?
When buying it is very much BUYER BEWARE, but if they don't know they need to beware and sent there's not a lot that can be done. In every generation, those who aren't aware of risks and don't ask the right questions of their solicitor and older and wiser friends, find themselves burned.
So what to do now? It will be possible to sell, but at the price minus the cost of lease extension plus something for the trouble someone else will have in sorting it. A cash buyer will buy it up and pay for the lease extension. It is possible for you to start the process of a formal lease extension and pass the process to the buyer and the buyer will pay the bill. Otherwise the buyer will have to wait 2 years and it will cost even more. A cash buyer will be your best bet, as they wont need a mortgage. They will be able to drive a hard bargain though, given your lack of other options.
You have suffered due to a number of things - lack of knowledge, but also the economic circumstances which occurred soon after you bought as MrsDenim said. 22 year olds buying are unusual and need lots of help and advice if they do so - from their solicitor but also family or friends around them too, for whatever reason you didn't have that or access it. At different times,msolicitors have been better/worse at pointing out things like this - partly related to whether they were a big worry at the time, and partly to do with them individually. Lots of solicitors wouldn't have made a big thing of this in 2006 if finance was easily available and there was nothing to suggest prices might tank or finance become unavailable or other things like that.
So, yes you are in a pretty unfortunate position but there's not a lot anyone can suggest to make a big difference. You will either need to stay put and borrow for the lease extension,mor try for a cash buyer and accept you won't get the market price of £60k because the market price isn't £60k with that lease length. In reality, you probably can't afford to move and will have to stay put, even though that's not what you want to do. Sorry that there's not a lot more anyone can say. Perhaps others will read this and learn something, but for you,nit has happened. I'd move away from thinking too much about who is to blame or looking to blame, but focus more on your next steps. It has happened.