Originally Posted by
Nimrod1965
I must be completely stupid then because I can't get anything under £2000, what dates are you using?
So don't use the multicity tool. Just get a quote for a return LHR-TLL for some random dates other a weekend in February. You should see the routings listed for connecting via HEL with BA flights to HEL and also BA codeshares of AY flights. Then just advance week by week to the date you need.