I went through this process last spring on my 2004 H33 and I believe the interior colors are the same as your H356. It took awhile to find out what colors and products Hunter used but i was able to get through this site and Hunter.
So if the colors are the same, here's what i did:
On the Mohawk website, go to AEROSOLS/TONER AEROSOLS/TONE FINISH TONERS.
The products requires are the M101-0205 (Medium Walnut), M101-0206 (Light Walnut) and if you need to touch up the back side of the seatees, M101-0249 (Perfect Brown).
I found that using any of the protectors listed on the Hunter instruction sheets changed the color of the finish and no longer matched.
Gently sand the area just to provide a rough surface for the toner to stick and apply very light coatings. have a rag ready to gently wipe down any access and then let dry. Spray an area a little wider than the affected area so as to blend the colors. Let dry and repeat if necessary. You'll want to cover any areas that are close to the area you want to fix and especially on the bottom cause there will be residue. Also note that a mask is highly recommended and you should have the boat fully open for ventilation.
I had several areas that needed some touching up and this process worded great and is very easy to do. Just take your time. Hope this helps.
Marc