I realise that with the right tools and determination it is possible to break-in to most houses and I am being purely selfish and fitting these locks so that a burglar will move on to another house where he knows he will be able to break-in with less effort.

I have fitted Mul T locks from CH Woods on Wakefield Road. The locks are reasonbly pick proof, bump proof and drill proof, they also have a weak point designed into them so that if anyone tries to snap the lock it breaks in a way that leaves part of the lock in place so that the key is still needed to unlock the door. To gain access to the lock a burglar usually has to break off the back plate of the handle. On most PVCu doors this is made of aluminium and is thin enough to grip and break off. I have therefore replaced them with handles that have solid metal back plates, stronger screws and stronger threaded sections. They also have a cover over the lock to make it even more difficult to gain access to it. When finding out what size locks to buy you need to remove the existing one. This is very easy to do if you have the key. The lock is held in the door by a single screw that goes in from the edge of the door so the door needs to be open to undo and remove this screw. Once the screw is removed you need to turn the key about 30 degrees to put the latch in line with the body of the lock, the lock should then simply slide out. If it does not then turn the key 30 degrees the other way. You then need to measure the distance from the centre of the screw hole to the front and the rear of the lock. I had 2 that were 40mm + 40mm and 2 that were 40mm + 50mm.
If you want to replace the handles you need to measure the distance between the widest part of the lock and and the centre of the spindle. On mine this was 9cms, or so I thought, apparently the actual size is 92mm. You also need to note the relative location of the screws.
The major complication I had was with the second conservatory door has a PVCu moulding covering the full door edge. First I had to remove the steel channel covering the edge, remove the covers from the screws and then unscrew and remove the moulding. This then gave me access to the screw holding the lock in place.

Having seen how all this fits together you should have no problem taking out your locks and replacing them with the newly  purchased ones. tought you might need to shorten the screws that come with the locks and handles.

The locks and handles were just over £40 each inc. VAT 

If you don't fancy doing it yourself (I was a bit concerned about taking the edge of the conservatory door off) you can call the number being given out by the Neighbourhood Policing Team. You also might want to talk to the Crime Prevention Officer - they can give you advice. There is no point in making your doors secure if there is some other easy way into your property.

The number for the S.P.E.E.D. Project is 01274 376028 or 07918 661667