Ow does (a)the ARCIC or (b) the BEM statement on the eucharist overcome historic differences on eucharistic theology

Some sources which have to be included:
1. G Jeanes, signs of Gods promise:Thomas Cranmers sccramental theology and book of common prayer (T&T clark 2008)
2WCC faith and order 111 , Baptism, Eucharist and ministry. (Wcc1982 available online(
3 P Bradshaw Eucharistc origins SPCK 2004

others at writers discression.

For info: my style is slightly informal