I can answer this correctly. As I contacted VOSA on the matter. This was their reply:
Responding to your mail of 6 March to DVSA with the above title.
I attach a link to a Department for Transport Briefing note on the subject:
http://www.google.co.uk/url?url=htt...QQFjAA&usg=AFQjCNFvrExZMJ2_P6ghOMNQjCrlr0JLQw
My reading of this at section 1.3 second bullet point is that if there is no child restraint available (because there is no seat belt available) then a child under 12 or under 1.35m height cannot travel in the rear of a vehicle. However this is potentially contradicted by the table at the beginning of the document tat says for children aged 3-11 and under 1.35 metres height that "child restraints must be used where seat belts fitted" suggesting that children of this age/ height can be carried if there are no belts at all. It leaves an unequivocable statement that children under 3 cannot travel in the rear without there being an appropriate child restraint.
This policy area is the responsibility of Department for Transport centrally rather than any of the Executive Agencies like DVSA. I have tried to contact colleagues at Department for Transport to clarify this today but have drawn a blank. I believe a Clare Broam is responsible for the specific department. I suggest you contact Department for Transport centrally using this link:
https://forms.dft.gov.uk/contact-dft-and-agencies/
I am sorry about this. I can answer virtually any question on road transport legislation but this legislation and the briefing notes provided are just impenetrable.
Steve Whitehart | Heavy Vehicle Technical Officer
Driver and Vehicle Standards Agency | Ellipse, Padley Road, Swansea SA1 8AN
Phone: 01792 454306, Fax: 01792 454387
So I emailed the DfT and eventually got this reply from them.
seats & seatbelts - 1970's Land Rover
Thank you for your enquiry about your Landrover.
For adults in the front and rear, seat belts must be used if available.
For children:-
in the front: all those up to 135cms in height (or 12 years or over, whichever comes first) must use the correct child seat/booster for their weight with no exceptions. If over 135cm or 12 years and above, they are treated for the purposes of this legislation as adults;
in the rear: where seat belts are fitted, than the same rules as for front seats apply but there are a few exceptions. One of those says that if belts are not fitted in the rear, then those 3 years and above may travel unrestrained. However, those under 3 years cannot travel – they must always use the correct baby/child seat for their weight in the front or rear.
Beware of sideways facing seats: there is no legal requirement for seat belts to be fitted in sideways facing seats – in an impact, anyone using a belt in a sideways facing seat is at increased risk of serious injury. But if seat belts are installed then they must be used by adults.
Please note especially that where seat belts are fitted, children who are legally required to use baby/child seats/boosters cannot travel in sideways facing seats because baby/child seats/boosters legally cannot be used in sideways facing seats. This does not mean that children may use an adult belt instead in these seats – it means that they cannot travel at all in sideways facing seats where belts are fitted. That may have an effect on carrying capacity. If extra seat belts are installed in the rear in order to carry children, they should be installed on forward or rearward facing seats – baby/child seats/boosters can be used in forward and rearward facing seats.
Nothing in seat belt wearing legislation prevents the carrying of adults in seats that do not have seat belts installed – even if other seats in the rear have belts fitted. It goes without saying however those seats with seat belts should be used first.
Remember that the police can take action if, in the judgement of an officer, passengers are being carried where “the manner in which they are carried is such that the use of the motor vehicle or trailer involves a danger of injury to any person”. The penalties for this offence are notably higher than for a seat belt wearing offence.
If you are likely to carry passengers without seat belts, you might consult your insurer about their attitude should there be a claim. And bear in mind that if there is an impact, the body of anyone unrestrained is likely to be a considerable risk to those seated in the front or elsewhere in the rear.
I hope this clarifies the position.
Yours sincerely,
Jeff Gilmore
Department for Transport
PO Correspondence
5/22 Great Minster House
33 Horseferry Road
LONDON
SW1P 4DR
You'll want to read it a couple of times to get all the points. But the jist is, if they are over 3 and you don't have belts, then yes it is legal. If you do have belts and they are over 3, but under 12/135cm then no.