Chris
If you Google Night OR Trickle vents you will see some illustrations. They are easy to fit, all you need
is a drill, 3mm or 4mm drill bits and a cross head screwdriver. One part which includes a fine mesh
screen to keep the mossies out fits on the outside. The other part which has a sliding/ opening action
fits on the inside.The ventilation is provided by drawing a pencil line across the top of the frame and drilling
a series of holes next to each other to create an almost complete slot. Clever buggers can join all the holes
together to create a slot, but either will suffice. The vent covers fit over the holes and are held in place with
the stainless screws that come with the vents. They do not effect security but improve ventilation throughout
the property.
Chris.
The locks you bought leave the window in a slightly open position.
This gap is ideal for burglars to slip in a crowbar and force open the window.
You can get the vents at Double Glazing component suppliers or good DIY stores and are quite cheap.