Skype on Plusnet Value - anything I need to do?

[#1]

My son-in-law has a Skype call arranged for tomorrow morning but his phone line is dead & unlikely to be fixed in time.
I've offered him use of my Plusnet connection. I'm on Plusnet Value & have used 4GB of my 10GB allowance.
Data rate on modem is currently showing 8128/448, although just did a test on Mybroadbandspeed and got 3937/364 (but I guess 6pm isn't the best time to do a speed test on a rural exchange)
Is there anything I can do temporarily to ensure he gets the best quality call?
Thanks
Martin

[#2]

I think you'll be fine. I used Skype (with video) over a 1750/448kbps connection.

[#3]

Should be fine. On a Skype call you can't receive any faster than the other party can send.  

[#4]

But if you are calling abroad you may find that they can send a lot faster than we can, so a Skype call can take a chunk out of your usage allowance.

[#5]

Worked fine. Thanks