I was wondering if anyone knows if its safe to combine 2 lots of defrosted EBM? For example if I have one lot dated say 07 May and another dated 12 May is it ok to put both into the same bottle to give to baby?

I can't see any reason why not if they were both frozen just after you expressed them - they haven't been in the freezer for long so they're both still fine to use. It's no different to putting each one in a separate bottle and giving her one after the other - just make sure you shake it first to mix it up well because the milk can separate out, so you know she's getting the right amounts of foremilk/hindmilk if she doesn't finish the bottle

Thanks