Casement Windows Swansea SA5. The MPN window fitters team specialise in casement windows and sash windows in Swansea SA5. Get in touch today for a quote on bespoke windows. serving Blaenymaes, Cwmdu, Cwmdu Industrial Estate, Felindre, Fforestfach, Gendros, Llangyfelach, Llewitha, Manselton, Penlan, Portmead, Tirdeunaw, Waunarlwydd, Swansea.