Did you notice the bit on your ticket about -

For information on our baggage policies please visit:
http://ba.com/baggage

Which takes you to the Checked Baggage section here:

http://www.britishairways.com/travel...c/en_gb#europe

Europe and all other international routes (including BA Cityflyer London City Airport routes)

Passenger Free checked allowance
Adults and children aged 2 years and over FIRST and Club World– 3 Bags
Club Europe and World Traveller Plus- 2 Bags
World Traveller and Euro Traveller – 1 Bag
Maximum dimensions per bag (H+W+L): 158cm (62in)
Maximum weight per bag: 23kg* (51lbs)

So, in answer to your question, I would say probably neither.