You ask about Catholics in Preston ca 1810. Sadly the parish registers for 1803 to 1813 have been missing for many years. The Censuses that jds1949 were compiled by the Parish Priest of the time. They have been transcribed for family historians in an attempt to fill the information gap.
Very recently, the other early registers for this Catholic chapel have been transcribed and published on CD. Have a look at the Catholic Family History site
http://catholicfhs.wordpress.com/2012/10/13/113/ which provides fuller information about it.
You should also check the marriage registers of the Anglican Parish Church (now the Minster) for details of possible marriages around this time.
Jim Lancaster (Bury, Lancs.)