@Geoff ******
you better hope that a simple bank statement is enough. If they actually want a letter from your pension provider showing the amount of income, that normally takes anywhere between 4 and 6 weeks to produce due to needing to work the future figures out.
I don't think its the bedding in of the system is what the problem is.
The problem imo, is them not requiring hard copys of the documents in the first place when using the postal option. That in my mind is all to do with them not wanting to store it, post it all back, needing A4 envelopes, weighing it all and due to costs, the Β£10 probably wouldn't cover the postage.