Originally Posted by
Swanhunter
BA don't publish through fares for European connections - commercial policy I guess as you would have to be nuts to connect via LHR for most European routings.
BA.com has been programmed to offer the only valid fare which will be the IATA YY price. If the IATA fate is more than the cheapest CE ticket (most likely D class) it will book you there instead. That bit is pretty normal.
It doesnt seem to be doing that . The YIF and CIF fares are EUR1220
The lowest BA fare from LHR-OSL which allows end-on-end ticketing for international fares, is the business fare whilst even the cheapest DUS-LHR allow end-on end. The BA LHR-OSL J fare is EUR774 ( with CIF at EUR725 ) with the O class FRA-LHR being EUR14 . Even the O class FRA-LHR allows end-on-end ticketing with any other BA fare ( unlike the LHR-OSL fares). Put the 2 together and then add taxes and would come out over EUR800 but less than the FRA-OSL YIF/CIF fares
EUR739 plus taxes of EUR108 would give a fare of EUR847 which would seem to be in the ballpark of what OP was being quoted so definitely doesn't seem like an error in pricing