OK. Disk Identifer reports
Unique Disc Identifier : [DVD-R:FUJIFILM03]
Disc & Book Type : [DVD-R] - [DVD-R]
Manufacturer Name : [Fuji Film]
Manufacturer ID : [FUJIFILM03]
Blank Disc Capacity : [2,298,496 Sectors = 4.71 GB (4.38 GiB)]
So it appears as though Fuji are the manufacturer.
As far as I am aware, my players are DVD -R compatible. When I do get the disks playing, they play well, without much garbage or pauses. I bought the DVD -R as -R is meant to be most compatible.
I will only burn disks when I am offline and therefore, disabling firewall should be OK. Having said that though I will not be disabling anti virus anymore as this IS risky due to trojans etc.
I had checked the box in DVD SHRINK to bookmark DVD -R
All my disks play on my PC with no problems.
I have run CD SPEED and at about 80% I get this error
ERROR - ILLEGAL MODE FOR THIS TRACK 
No idea what this means
Upto then I had a faultless curve.