MG TA cross brace

[gjkathome]

Hi, the attached image is a brace which strengthens the wooden frame of a pre-war MG TA. It's mild steel with a more-or-less semi-circular cross-section. I need to lengthen the two short sections arrowed by 4mm. I'm not sure of the best approach. Cut, build up one end with weld and re-join? Weld in a short semi-circular piece? Something else? I have a Clarke 135 TE welder.
Thanks for any advice.

 

[CompoSimmonite]

Trim down the wood frame by 4mm ?

 

[addjunkie]

Use a piece of flat say 2 mm on the back, to bridge the cut, then fill the 4mm gap with weld.

 

[OJCar]

Does the brace go somewhere that shows or is it out of sight?

 

[minimutly]

Make a mild steel insert, cut and insert the insert, leaving 4mm gap. Mig weld it up.

 

[gjkathome]

Thanks for all the suggestions. The part does show but all that much. It's pretty much hidden behind the seats.
If I am filling the gap with weld should I set the welder to its highest power? I should have said that the cross section is about 20 mm wide by 10 mm deep.