Two way elite - toddler unclipping seat belt connection

[Finlaggan]

Can anyone help? DS will be two in September and today during a lengthy drive he performed his latest trick which was to stick his hand down the side of the car seat and unclip the seatbelt connection therefore making the car seat unconnected to the belt. Thankfully DD spotted him doing it as we were travelling down the motorway.
He is RF in a Britax TWE.

He continued to do it intermittently throughout the journey. His shoulder straps are tight I'm not sure if he just has really long arms or something but clearly thought it entertaining enough to do it more than once whilst saying uh-oh and shout "more! More!"

Can anyone advise of a product or method of strapping in which would stop him from doing it?

Thanks.

I looked at buying one of these www.bucklesafe.co.uk/ to cover the buckle of the seatbelt holding my Britax Multi Tech II in place. I wanted it because I have three children, so I didn't want the child sitting next to the ERF seat unfastening the wrong seatbelt. I couldn't put the Multi Tech on the seat with the buckle away from the other two buckles (this is the seat behind the driver in our car) because of the lack of legroom it creates for the driver (I have long legs!)

Anyway, I didn't bother in the end because my car (Peugeot 5008) has the buckles recessed into the seats so they are not suitable for the Bucklesafe. It's DS who sits next to DD2 in the Multi Tech and he is 8 so he's more than capable of checking which buckle he is undoing. Also there is plenty of space between the child seats to see the buckles clearly.

Could be an option for you, depending on your seatbelt buckles.

that's brilliant thanks alice looks like it will do the job.