There are quite a lot of Jeremiah Allens around the Luton area, so I wouldn't count on that one being certain either. Remember that you're not a long way away from Hertfordshire, so it's quite possible that your Jeremiah wasn't even born in Bedfordshire.
There are certain burials you may not have seen.
13 Feb 1784 Jeremiah Allen of Stopsley
14 Oct 1803 Hannah Allen, widow, of Stopsley, aged 80
14 Oct 1807 Elizabeth Allen of Stopsley, aged 64, fever
It's quite probable that Jeremiah (the younger) was buried after 1812, in which case the burial register should give his age at death.