For Clarificaion from here
Child Car Seats : The Law : From September 06 : FAQ
Q: I have sideways facing seats in my vehicle, can I still carry children in them from September?
A: Sideways facing seats are not a safe way to travel. An adult seat belt is not designed to restrain an occupant who is sitting sidewards, and the same applies to child seats.
Seats tested to UN ECE R44 are not designed, or intended for, vehicle's sidewards facing seats, and do not count as the correct restraint for the child. A child restraint cannot be used on a sidewards facing seat.
And according to Dft website
Think! | Children: Child car seats
no Children at all may uise a side facing seat (Though I doubt their advice/statements are legally correct)
3. What do I do if my vehicle -
- has no seat belts, or no rear seat belts?
If a vehicle has no seat belts - if it's a classic car, for example - a child aged 3 years and over is allowed to travel in a rear seat unrestrained.
A child under 3 years old may not travel in cars, vans or goods vehicles which do not have seat belts.
- only has lap belts?
A child is not exempt from using a child restraint in a seat with only a lap belt.
It is difficult to find a child seat or booster that the manufacturer has designed to be used just with a lap belt and you may need to talk to a specialist supplier. Alternatively, consider fitting a lap and diagonal belt in the car. If a manufacturer says that a particular child restraint system is only suitable for use with a lap and diagonal belt, or that their product should not be used with a lap belt only, you should take this seriously.
A lap belt doesn't provide maximum protection for a child, whether it's used with a booster or not. The child's unrestrained upper body is liable to pivot around the lap belt with the increased risk of injury to the soft tissues of the abdomen. A lap belt may also be difficult to fit properly on a child.
Children may need to be moved round the vehicle so that they use seats where their child seats/boosters can be fitted, including a front seat - but check advice about children and air-bags - see Qs 4 and 5.
- has no rear seats?
Apart from those in rear-facing seats when there is an active front air-bag, children can travel in the front seat of any vehicle provided they are properly restrained. This includes 2-seaters or convertibles, even if the top is down.
See more on baby seats and air bags - see Q5.
See more on child seats and air bags - see Q6.
- has sideways-facing seats?
There's no legal requirement to fit seat belts in sideways-facing seats. The human body bends forward from the waist - not sideways - so the potential for internal and spinal injury is high if a passenger uses a seat belt in a sideways-facing seat. For similar reasons child seats and boosters cannot be approved for using in a sideways-facing seat.
Therefore, a child who is required to use a child seat/booster (ie, all those under 135 cm tall who are also under 12 years old) cannot travel in a sideways-facing seat. A child who needs to use a child seat or booster must use a forward or rear-facing seat.
If anyone knows of any legally binding ruling or official website that contradicts the above info Please feel free to post a link. Where childrens lives are concerned I don't think anyone posting "well I don't agree because" is worth the screen space they take up.