Hi Cloe,
In the 1841 census ages were often rounded to nearest 5, which is why some dates could seem wrong.
I will look for Lowes in Haltwhistle 1841 if you can give me an idea of address or narrow it down a bit. - Haltwhistle parish includes Bellister, Blenkinsopp, E. Coanwood, Featherstone, Hartley-Burn, Henshaw, Melkridge, Plainmellor, Ridley, Thirwall, Thorne, and Haltwhistle itself covers 8 sections so there's a lot to look through, not name or street indexed!
Barbara