You Do Need power plug adapter while traveling from Guadeloupe to Northern Ireland.

Here is Why You Need An Adapter

The outlet and plug type used in Northern Ireland is G and in Guadeloupe are C and E. This is how they look like.

Guadeloupe

In Guadeloupe, outlets of type C and E are in use.

Type C

Type E

Northern Ireland

In Northern Ireland, outlets of type G are in use.

Type G