Winrar help

I have extracted a huge file out of multiple rars (part1.rar, part2.rar etc…) however I forgot to add the last part to the folder while extracting.

The extraction went without a glitch so I deleted all small rars, but when I opened the big RAR it gives me a nice “unexpected end of archive” error.

I do however have the last missing puzzle piece now, does anyone know how I could stitch the big rar and the small rar together ?

Thanks

mlk