Seatbelt extenders,anyone used them ??

[Scooby_Doo]

I bought a Graco booster seat,with the backrest and headrest,for my grandson to go in the back seat of my wife's W169 "A" class.
PROBLEM, the seat belt clip is mounted so rigidly in the seat base that you can't get the belt to lock in place easily as the booster seat base sits flush with the mounting. The only way to overcome this is to fit a small seat belt extender onto the seat base mounting to pull it away from the booster base.
Anybody else had to do this and is it a safe option ??

 

[Driver15]

Are you able to put the seat in the other side of the car where there's the 2 seat belt connectors ? So you then put the belt buckle into the middle seat seatbelt clasp ? May gain you a couple of extra inches.

 

[Scooby_Doo]

Good thinking Batman.Will try it tonight.Probably work because the seat will be a few inches from the holder. Thanks.