"receive from device"

No, but instead just copy the ones you want, or if you find it easier delete all data in BC then load everything from your device.

I seem to be making vary heavy weather of using Basecamp compared to Mapsource. I've been through all the tutorials, but the amount of stuff displayed on the map is fogging a lot of what I want to do.

Specifically, I followed one of my friends last weekend, and would like to repeat the route we took. I just opened Basecamp and clicked receive from device, clicked on the list with today's date, and the map was covered with routes and tracks.

How do I just see the route from last Sunday ?

You need to create a list in BC with a single route in it to just see only the one route on the map.

You could simply create a new List: File > New > List and give it a name and drag the route from last Sunday to that empty list and it will be copied there (or use Send To:.. or use Copy and Paste).

Alternatively you could connect your device and just copy the route of interest from the device to the empty folder:

1. Connect your device and click on its Internal Storage folder to see the device's contents (you can sort these by item type using the icons at the bottom if that helps).

2. Identify last Sunday's route from the date (I usually keep the YYYY-MM-DD for ease of sorting but replace the hr/min/sec with the track name to aid finding it again).

3 Click on the track and Send To... the previously named folder (or use Copy and Paste or use drag and drop). Click on this folder and you should just have the single track visible on the BC map. 

OK, using Windows Explorer on my PC, I found a folder called GPX and it has files with the appropriate dates on them, so I can do sensible things with that, thank you.

However, I think you mean open Base Camp, click on receive from device, and click on the Sat Nav rather than the memory card, and yes, under Devices, half way down the screen, I can see files with the right date and a pair of feet by them.

Thank you.