Hello Handm,
Thank you for going to the trouble of replying. It's quite possible that they were still in Ireland in 1841.
If the 1851 census is indexed, would you mind looking for a Joseph Bonnon. The reason being - on the 1861 census, there are two of them born in Ireland - one living in Oldbury and one living in Church, Lancashire. Both are about the same age.
If it's too much trouble, it's OK.
Thanks again.
Marie.