At first glance it does look like Nelbank in the image of the register, but a comparison with other entries on the page suggests it's actually Welbank. There's a baptism with the surname Walker about 6 entries higher up the page, and the first letter is the same. Upper case 'N' (see Nupt: at the start of the line, also November etc) starts in the same way, but it doesn't have the curl/hook on the bottom of the right hand upright.
Also important to note is that Ann was described as a widow, so this probably won't be her birth surname.