Lap belt and booster seat

[zippytiptoes]

Can you use a backless booster seat in the middle position in your car (an older Pajero) with just a lap belt? I've been told I can't do anything about the fact that I have just two diagonal seat belts

No, the whole point of a booster seat is to raise the child up so that the seat belt fits properly over the shoulder.
There are stage two child seats that can be fitted using just a lap belt though if you are able to swap places.

BRITAX FRONTIER 85

Unit price £130 - £150.00
Delivery from USA £42.00 - £97.00
Import duty £26.00 - £56.00
See 'YouTube', Google etc

You'll need a pair of narrow seats either side as the Frontier is 19.5 inches wide, but the frontier is the only one I could find that kept ours in the integral five point harness up to 85lb in weight and 57inches in height yet only required a lap belt to fix it to the car's seat.

A few emails to Britax might get them to sell the frontier in the UK. It's that or swallow the cost, which is infinitly preferable to an abdominal injury that is extremely likely with a lap belt used either with or without a booster seat.

you could use a britax eclipse in the middle for your youngest?it secures with only a lapbelt.

No- booster seats must not be used with just a lap belt.

What are the other cars eats being used?

theres also the britax two way elite which is from birth and can be used with only a lapbelt.