No. The local authority issue plans based on hours of support, but this is linked to a figure of top up funding. The school determines how best to allocate that funding. That may be through the use of specialist equipment, counselling, learning mentor support, group input, etc.
It can mean that a child works 1:1 with an adult or there may be one or two other children with them too. The concept is to always foster independence at the right moment, and simply put, having an adult alongside them all day every day does not allow a child to develop any independence skills which they will need as they get older. It is usually a combination of all of the above and possibly more depending on the individual needs of the pupil.
For further information, please refer back to your child's EHCP plan or ask the SENCOs for further information.