(24 Mar 2015, 9:00 pm)Kuyoyo wrote Streetlites 1591/7/8 have now arrived at Jesmond depot. 1597 is confirmed to be NK15AAX.
Information from Robert Smallwood on 'Arriva Bus News and Photos' Group on Facebook
1578 arrived at Darlington to be used for familiarisation I understand.
Sapphire launches for 22/24 programmed for w/c 12th April, not sure which day yet though! The MAX ones on the X1 will probably go out before then