sensor & focusing screen cleaning Essex

[suggs]

i want to have it cleaned as can see some dust spots in my images in certain lights and some marks can be seen in the view finder, i dont think i want to risk a diy job plus i will be selling the camera shortly so want to make sure its done correctly..

am i correct in that marks on the focus screen and mirror dont show in images so the dust must be on the sensor ? lenses are clean..

im in South Essex so if anyone has any recommendations or if anyone on here does cleaning etc then please let me know..


cheers