Hello Mark
I was so pleased to see your reply. You have found a baptism record that I've searched for so long for! Perhaps there will be a record of an older child Peter baptised before Matthew if I search St Mary Moorfields.
I do have quite a bit of information which I'll gladly share with you, please could you email me direct: sue.osborne@live.co.uk and we can discuss the best way of passing on the info we have.
Best regards Sue