His birth index:

First name(s)         Peter R
Last name             Hennell
Birth quarter         1
Birth year            1944
Mother's maiden name  Hughes
District              Hitchin
County                Hertfordshire
Country               England
Volume                3A
Page                  1789
Record set            England & Wales Births 1837-2006
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There are two apparent marriages for a Peter R Hennell:

Year  Bride              Location
1974  Anita F Nissa      Merton district, Surrey
1979  Kathleen Dunbabin  Cambridge district

I think it will need a marriage certificate to sort this out.  It could be that both marriages were his.

There were no children registered for the first marriage from 1974 to 1994.
Nor for the Dunbabin marriage from 1979 to 2009.
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No death found for Peter Robert Hennell, he could well still be alive and in his late seventies.
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