JPs and Settlement certificates

I have been reading some Lancashire Settlement Certs today at Lancashire Archives and I note that while they are all originated by churchwardens and overseers of the poor, all are authorised by two magistrates. Does this mean somebody had to go to the Quarter Sessions before the person in question could actually move to the new location? Or was it Petty Sessions? Or did the parish / township officers have to ride about knocking on the doors of JPs to get their signatures and seals?
All the books are full of legal stuff about how you gain settlement, but nothing says how it actually worked in practice. Is there something in a Thomas Hardy novel? (He's good on things like that)
What I'm trying to do is date a settlement certificate (which is definitely pre 1735) whose date has rubbed off, but I can see the names of the JPs. The only other settlement certificate I have found with the same two JPs was 21 May 1729, so can I assume that was a sitting of the court, and possibly the only one where the two JPs sat together, or was it just a random date?
Barbara

To gain settlement in another parish, you had to prove you will not be a burden within that Parish. That is, you needed to have a trade, or income, or your skills were needed within that parish. That is my understanding.

If you gained settlement, and became a burden on the Poor releif, they could apply to the Parish of your origins for payment, or have you removed.

My question really is - if a man got an offer of a job in a different area, but had to take a settlement certificate with him (proving who was responsible for his relief if he became poor), could he ask for a settlement certificate today, get one tomorrow and be off? Or did he have to ask for one, then wait up to three months for the next Quarter Sessions for his certificate to be approved and issued by the magistrates?