I know you are looking for Thomas SKINNER but here's a bit more about the William SKINNER you have mentioned.
The Old Bailey site has the account of the trial of
William SKINNER, aged 22, 4 July 1833.
On 10 June 1833 he stole a handkerchief worth one shilling, from a William EDWARDS living at 89 Cheapside. The crime took place around Ludgate Hill, Sadlers Wells, Drury Lane, St Brides area of London. No family details given though and as it's an area with a fairly high population as well as an area where many people would work/visit there are no clues as to his residence.
http://www.oldbaileyonline.org/browse.jsp?id=t18330704-88&div=t18330704-88&terms=skinner#highlightTasmania, Australia, Convict Court and Selected Records,
The Register Alphabetical register of the appropriation of convicts in the North, 1833-1835, states that William's "Native Place" is Islington
This chap arrived on the ship
John and on the 1835 convict muster is shown as having been assigned to Mr T Mathews (no district given). By 1841 he was listed as "Free by servitude".
However the ref given by Debra states that in May 1841 he was to be sent for trial for receiving stolen property from 2 bushrangers,knowing it to have been stolen and assisting them to escape.
Judith