If you're located in the Pembrokeshire area do give Robin at Pembrokeshire Stoves a call - he's personally installed many a Windkat!
https://pembrokeshirestoves.co.uk/
Pembrokeshire Stoves
Fachongle Isaf, Cilgwyn,Pembrokeshire, SA42 0QR.
Phone: 01239 821166 / 07812346780