Hi Terry,
The Maelor waters are below Llangollen and are very heavily fished, and while the Llangollen waters receive a certain amount of pressure there is more water to go at, about 10 miles of excellent fly water.
Llangollen now have a website
http://www.llangollenangling.net/
Day tickets are also available for Midland Fly - but they won't let you fish the salmon pools.
If you don't mind the extra travelling, then the Bala waters are lovely with some excellent fishing.
http://www.balawales.com/angling/
There are a few other day ticket waters listed on my friends site, have a look at
http://www.grayling.pwp.blueyonder.co.uk/index10.htm
Although if you are going to travel across to the Dee or Bala, to help your friend catch his first grayling, then it may also be worth considering the middle reaches of the Eden on the "Go Wild in Eden" tickets?
Hope that helps