Readers’ forum: Place of supply

I have a VAT-registered client who provides cyber-security training mainly to government departments and other non-corporate entities.

For one contract with the Foreign Commonwealth and Development Office (FCDO) he and two staff will travel to Belgium to deliver courses for staff at a Belgian government department. As the work is being carried out in Belgium does he need to register for VAT in that country and charge Belgian VAT on his invoice(s) to the FCDO?

He has another contract for a big church in Ireland working directly for the church but this training will be performed online i.e. with my client delivering face-to-face training but with the church staff being in Dublin and my client at his office in London. What is the VAT position here?

Finally if my client uses UK-based subcontractors to help with the Belgian project...