Getting rid of wasps nest in cavity wall

joylikes2shop

Has any one in the greater Belfast area, any experience of using a professional company to get rid of a wasps nests within a cavity wall ?
Wasps have set up home in the cavity (top & bottom corners) of a bedroom room window. 

No nests are visible but there is a lot of wasp activity. 

Have used foam spray on a visible nest which  worked well, but it hasn’t worked on the holes in the corner of the windows. 

Grateful for any experience or advice about local companies.