Information regarding Ultra Low Emission Vehicles Grant was requested from Office for Low Emission Vehicles (OLEV) in Febuary 2016. At that time their answer was:
The Government remains committed to supporting the zero emission motorcycle industry and OLEV officials have worked closely with the industry over the summer on the technical details and eligibility criteria for the scheme. Following the successful outcome of the Spending Review in November last year OLEV is now in the process of confirming the allocation of funds to existing and future ULEV support schemes for which it is responsible. We will provide further information on the next steps for the Plug-in Motorcycle Grant scheme as soon as they are known. OLEV continues to work closely with the motorcycle industry and other key stakeholders as it finalises the details of the scheme including the grant level, eligibility criteria and the logistics of the grant. This includes considering precisely what eligibility criteria might be used for the grant scheme, how vehicles would then be assessed against the criteria and registered, how the grant scheme might be implemented for those purchasing ePTWs, for those manufacturing ePTWs and for those selling them. You can keep up to date with any announcements here: @OLEVgovuk
So far no updated information provided either on their Website or Twitter.
Unfortunatelly, it doesn't look like Zero Motorcycles are willing to cooperate with UK govenment towards providing a clear information. Until further information provided, please, do not consider positively.
Updated information regarding Zero Motorcycles grant eligibility can be found at Twitter https://twitter.com/OLEVgovuk or at the OLEV website https://www.gov.uk/government/organisations/office-for-low-emission-vehicles as well as Grant Eligible Vehicle list at GOV.UK https://www.gov.uk/plug-in-car-van-grants/eligibility