SAOʹs are relatively rare. The average LA issues only 2 each year though their is a wide variation with many never issuing any. Since they are extremely expensive, LAʹs usually prefer to attempt every other avenue first and even where they are issued it does not inevitably mean that you must send your child to school or even that you will be going to court to defend your rights.
Should you be issued with an SAO my advice would be to see a Lawyer who is knowledgeable of home education and the education act. To find such a person you might contact the HE UK mailing list or another forum.
An SAO is a School Attendance Order Which is covered under the Education Act 1996,
Sections 437 through 443) section 437 says:
The procedure is that if the LEA believe that the parents have failed to provide an education suitable to the childʹs age, ability and aptitude and any special needʹs s/he may have [education act 1996 s7] then they should make informal enquiries. If the parents fail to respond or do so in a way that a reasonable person would conclude that no education was being provided and they believe it is expedient to do so (see also section 175 of the Education Act 2002) then they may decide to issue an SAO.
The Order will name a school (which the parents may appeal to change) and offer the parents a period of 15 days to provide further evidence of suitable home education. The LA must explain in what way the parents response is unsuitable and be responsive to the parents during this time.
Should the parents fail to register the child at the named school the LEA may then go on to prosecute them for failure to provide a suitable education. However the court will also examine evidence presented to the court that they are offering such an education. The level of evidence required is that which would convince a reasonable person on the balance of probability. Importantly the court is interested in what is happening at that time, not what was happening when the order was first issued and that it is up to you what evidence you supply and how you supply it.