Because UK airport security is usually very inflexible in such unusual cases (they provide great service for 'classic' disabilities such as wheelchair). Also t

Because UK airport security is usually very inflexible in such unusual cases (they provide great service for 'classic' disabilities such as wheelchair). Also the fact they travel from Heathrow (most overcrowded and busiest airport in Europe) and not from Gatwick, Stansted or other friendlier airport.