Hi again, just a bit more info. I have had another go today at finding the best solution. several sms apps will display on the lock screen but then disapear after a set time, no good if you missed it as it arrived.
I have been playing with the Nils app before and I am unable to get contact pictures to display next to messages, even after trying several sms apps and being in touch with the developer.
But the best I've managed so far is as follows. A app called
iOS 7 Lock Screen Theme by huntdevs gives a plain lock screen which can slide to reveal a pin code screen. On the plain screen you can then use
NiLS Lockscreen Notifications by Roymam this will then display sms and other notifications on the lockscreen, these remain on the screen untill opened, even if the screen times out and is turned back on manually, furthermore you have the ability to reply to them from within the app whilst still locked.
Warning as I said earlier there is a facility to disable the home button but the recent app button is still active meaning that any apps used recently have the ability to be opened without unlocking the phone. Further more the pin lock screen gives you access to the emergenecy dial function and sadly again where as the default lock screen will only let you dial an emergency number, this app will let you see all of your contacts and further more dial any number you want!!
One final thing the ios7 locker does give you access to the functions of the Iphone from the slide at the bottom of the screen and for me the added advantage of this app over several of the others is that the phone function icon is missing (all be it available through the emergency function).
hope tihs helps.