Hi Penninah
No, you have all the siblings - we show them as Joseph bap. 12 Feb 1815, Andrew born 1816 but baptised 1820 at the same time as Gad who was born 1819, then Edward - no birth date but baptised 1829 at the same time as George born c. 1823 and Martha born 1829 (they obviously believed in baptising a job lot!).
You have also been in contact today with my husband, Simon Leather, Chair of the LFHS, via his work email, re. Joseph Leather b. 1787 to Joseph and Martha (Moseley) Leather. We have him as part of the tree that I mentioned in my previous email, which goes back to the 1540s, which several of our members have contributed to. It's too complicated to explain by email! We don't have these trees in an easy format to transmit - they were all done in Word some time ago and have been added to over the years. You may have information that we don't or amendments to make as this is a very complicated tree!
Leather Family Trees is available via the LFHS in hard copy or on CD - I would have to check the cost for you if you are interested.
Best wishes.