Well I escalated as suggested and the response was almost immediate:
Thank you for the recent email and letter you sent to our contact centre.
My name is xxx xxx and I work within the Senior Customer Contacts Team here in Norwich. The contact centre have shared your correspondence with me and I wanted to make direct contact as quickly as possible.
Please allow me to begin by offering my most sincere apologies for the inconvenience you were caused owing to our staff providing the incorrect information. This is not acceptable and is far from the level of customer service we would expect. All of our staff are highly trained in both ticketing and customer service and therefore it is with deep regret we have not met your expectations, or our own.
The ticket you were using to Manchester was valid as you are aware, and staff should have been able to check this without delay. As you will appreciate, there are thousands of ticket combinations in the national rail booking system, all of which have differing restrictions. Our Revenue and station staff all receive ticket training and therefore this is quite an isolated incident as it is very rare they would misinform a customer. We have acted quickly in regards to the incident and one of our Revenue Protection Managers is dealing with this matter directly internally.
Whilst I cannot disclose the action taken or training that is offered due to data protection, I can assure you that this is being addressed. The Inspector will be spoken to and made aware of the error, and a brief will also be provided to customer service staff so that we can prevent this from happening again.
I do understand that this has caused you great inconvenience and I am genuinely sorry about that. Whilst it cannot make up for the experience you had, I would like to refund your ticket in full by way of a bacs payment. In addition, I would also like to offer you a future complimentary return journey on the Greater Anglia network (a return to London for example).
So that I can make the bacs payment, please can you confirm your account holder name, number and sort code? I will then set the payment up so it is in your account within the next 20 days, although it is usually faster. In addition, the complimentary journey is open and you are welcome to use this whenever you wish. Please just give me one weeks notice and let me know the journey information/dates so that I can then post this out to you.
I can only apologise once again for this awful experience and I hope that it does not deter you from using our services again in the future.
Thank you for taking the time to make us aware of the incidents.
Regards,
So they have acknowledged their mistakes. Still alarming that THREE members of staff can be so wrong ~ a ticket inspector, guy on information desk, and the first responder from customer services. And whilst it is true there are lots of tickets, off peak returns for travel outside the NSE area must be quite common on the gate line at Liverpool Street?
Anyway, I may respond further, but thanks for your help everyone!