Merging sections of 2 GPS/GPX files???

I suggest using Garmin Basecamp. You can download it for free.

Then import both GPX files into Basecamp,
Select both tracks in the list, and go to Edit menu -> Advanced -> Join the selected tracks.
Then you can export as a GPX file.

thank you!

that did the trick

I took at a break at a café and accidently hit save on the garmin - so kind of annoying but fixed.

I tried to do this but there is no Advanced option on the Edit menu in Basecamp. I am using v 4.4.6 Basecamp on a Mac.

Basecamp is slightly different on a Mac. If you get no help here try posting your query in the BaseCamp Mac forum .... But try searching there first as the question might already have been asked/answered.

This may do the trick. Import the multiple GPX files into BaseCamp (Mac). Select the new items within the Transfer field while holding down Command. Then right-click on one of the highlighted items and choose Join Tracks. Next, highlight the new item BaseCamp just created, choose File > Export "Transfer". That should give you one single GPX file.

I had trouble with this for a long time but got it figured out a while ago and have been using BaseCamp for some time to edit my tracks. I wrote a tutorial on my blog that could help. I also covered a few other problems like file sizes being too big and how to cut unwanted parts off of an activity.

http://outdooroutlier.blogspot.com/2015/05/how-to-edit-gpx-data-to-make-useable.html