The type of lock recommended is extremely easy to fit (one screw) and it might be worth checking with your local police station, in our area if you have been the subject of burglary they are fitting them free. Also have a word with a reputable locksmith, they are usually very helpful.
Thanks guys, CCTV sounds like a good investment too, i'm abit weary about lighting as my neighbour has a flood light in their back garden which turns on in the middle of the night if a cat walks by. Not the best thing if your garden backs onto another house!
Most household insurance policies now state the type of locks required as a minimum requirement, so perhaps work on that advice.
At the end of the day, no matter what you fit or use, there are ways of gaining entry, and professional thieves, police and insurance companies know this.
We have cctv, alarms and two robust dog's, but they didn't stop someone from putting their foot 'accidently' through an outbuilding roof the other night. Had they dropped the twelve feet to a concrete floor or among various solid machinery, then I suppose an ambulance chaser would be knocking the door by now?.
If you have Wood Door frames, you need to screw long screws into the fram from inside to external just so they do not come out at the outside, these need to be near the the locking bolt that is turned by the Key, this will stop Splitting of the Frame under bashing, bolts are best put at the top of doors as you cannot get any fours behind these to burst through the door, fit good 5 lever security locks with hardened pins in the bolt to stop sawing through. any extra locks will not come a miss but you need the above for external exit security. if they are determined to get in they will find a way. You have to think like a Burglar to stop them. there are other easier ways of getting into a house, ask what would you do if you locked yourself out