If he marriage took place in Ireland and Catherine was from Louth, the Shovelins (many variant forms) where likely to be from one of the adjacent Monaghan parishes and indeed two Catholic parishes Inniskeen and Killanny span both counties where Shevelins dwelt and it was from these parishes that a large amount of families emigrated to Consett to work in the newly established ironworks so I would concentrate your research in that district.
The Night of the Big Wind, 6th January 1839, was exactly 70 years earlier than the introduction of the Old Age Pension for over 70 year olds, 1st January 1909 and those elderly Irish who weren't sure of their age could determine it by whether they were born before or after the The Night of the Big Wind, but because they could not prove it with a birth certificate, as registration did not commence until 1864 and many baptismal records were lost during the Famine they could apply for a search of the 1841 and 1851 census returns to prove their age. Some of these census records have survived and are a wonderful source if you are one of the lucky ones whose records have survived.
Good luck
J.T.A.