Hello, I discovered only yesterday that Hertford North is 'enabled' for Oyster. I have a PAYG oyster card with Senior Railcard added. I made a journey this afternoon from Hertford North to Warren St, changing at Highbury & Islington. My Oyster has been charged £6.30. I've been buying tickets regularly for this journey from my usual retailer (Avanti app) and usually pay twice that if not more. Looking up the fare tonight it's quoted as £11.00. Trainsplit are quoting £8 something. Please can anyone explain what is going in here and am I right to feel totally ripped off until now... I really don't understand the UK fare system and in spite of travelling over 20,000 miles a year on business how is an ordinary user expected to get best value from an opaque system such as we have here. Forgive me if I'm just asking too much but I'm feeling pretty aggrieved about this revelation stumbled on with this particular journey. Thank-you...