VAT and EU jurisdictions

uk vat registered business, which does work in the uk and abroad.  [ services are expenses reimbursement, reports commissioned+ recharged plus time and materials ]

A Current client is Swiss based + Swiss VAT registered, some of the  preparatory scope is done in the uk and most is done in this instance in switzerland .  What is the UK co's  invoice Vat position. Another project for them will be solely uk based, + again delivered and billed to Switzerland - what is the invoice VAT position if different.   Cumulative work for the client could be  £100k pa, do they need to register for VAT in Switz ?

Apart from Switzerland similar scopes could be contrcted within other EU states,  so I am assuming if you respond that they need toregister abroad,  then really each state limits would need to be investigated.  is there a summary which shows EU meember states limits before uk cos need to register there ?