The book "The Tool Chest of Benjamin Seaton" has a chart of chisel shapes (page 66) which from the shape of the shoulders suggests the Ibbotson parer is from the first half of the nineteenth century. BPM2 (which isn't infallible) gives Thomas Ibbotson's trading dates at Paternoster Row, Sheffield as 1825 - 1909; Schaffer and McConnell in "Handsaw Makers of Britain" give the same firm dates of 1833 - 1879.
From that, it seems quite likely that the Ibbotson chisel dates from the second quarter of the 19th century.
The Moulson Brothers is not quite so easy to pin down by shape, being more a small mortice chisel, but both references have Moulson Brothers starting to trade in 1824, and going on well into the late 19th century.