I didn't think of this before ................I only thought of it as I am doing the day 1 paperwork for tomorrow.
but I use two different names in day to day life.... But usually my official documents have my official birth name but nevertheless I tend to use one more than the other.
Let's say for example my surname is: Smith-Warner* but I usually use the surname: Warner (and drop Smith)
What do I do? Do I really need to tell them any other names I use? and if so ....how , seeing as I didn't put it on my other form.
And whilst we're on this..... (small and distant query I know) ...... what name is put on my warrant card etc....? Do I have a choice?
Before you ask yes this is a met query and indeed I altered my name here so nobody knows 
It doesn't matter at all what you 'normally use'. What matters is what your official documents say, which is indeed your official name.
I can't do a PNC check on a Michael Richard Luke-Smith, when he normally uses the name of Michael Smith. Well I can but it's long winded and can take up countless of hours.
If you have put anything wrong or missed out bits such as your full name, don't worry the world isn't going to end, before you are dismissed from Day 1, a recruitment officer holds an audit check on your documents so this is the time you can ask questions and fill in the blank.
Chill, and good luck Jonathan. Try to keep these questions in the respective pinned/floating threads which have been setup to prevent clogging of the forum.