Essential information:
https://www.gov.uk/foreign-travel-advice/armenia
and
http://wikitravel.org/en/Armenia
All airlines serving Zvartnots International Airport are listed here:
https://en.wikipedia.org/wiki/Zvartnots_International_Airport#Scheduled_flights
That suggests the following airports might offer useful interchange points:
Moscow Domodedovo (via BA ex Heathrow, feeding into S7, VIM or Ural Airlines)
Moscow Sheremetyevo (via Aeroflot ex Heathrow, feeding into their own services)
Paris CDG (via Air France from Newcastle, Manchester or Heathrow, feeding into their own services - or using BMI from Bristol, BA from Heathrow, easyJet from Belfast/Bristol/Edinburgh/Glasgow/Edinburgh/Gatwick/Luton/Southend/Manchester, FlyBe from Birmingham/Cardiff/Exeter/London City/Manchester, Jet 2 from Leed-Bradford or Vueling from Gatwick for the first section)
Warsaw Chopin (with LOT ex Heathrow, feeding into their own services - or using BA from Heathrow or Wizz from Aberdeen/Birmingham/Bristol/Doncaster-Sheffield/Glasgow/Liverpool/Luton)
Vienna (with Austrian Airlines ex Heathrow or Manchester, feeding into their own services - or with BA from Gatwick/Heathrow, easyJet from Bristol/Edinburgh/Gatwick/Luton/Manchester, Eurowings from Stansted or Jet 2 from Edinburgh/Belfast/Leeds-Bradford/Newcastle for the first section)
Minsk (with Belavia ex Gatwick, feeding into their own services)
Athens (with Aegean ex Heathrow/Birmingham/Gatwick/Manchester, feeding into their own services - or with BA from Heathrow, easyJet from Edinburgh/Gatwick/Manchester or Ryanair from Stansted for the first section)
Kiev Boryspil (with Ukraine International ex Gatwick, feeding into their own services - or with BA from Heathrow for the first section)
Prague (with Czech Airlines ex Birmingham/Edinburgh/Liverpool, feeding into their own services - or with BA from Heathrow, easyJet from Bristol/Edinburgh/Gatwick/Stansted, Jet2 from Birmingham/Belfast/Edinburgh/Glasgow/Leeds-Bradford/Manchester/Newcastle/East Midlands, Norwegian Air Shuttle from Gatwick, SmartWings from Gatwick or Wizz from Luton for the first section)
Surely there must be at least one route there that offers you decent connections!