Panasonic DMR E55 recording problem

I have had my Panasonic DMR E55 (UK model) for about 2 and half years but have only recorded about 40 DVDs. I have had no problems recording or playback until I tried to finalize a disc I had recorded off air and it failed to finalize. This is a vebatim x8 disc. I then tried to record with a TDK DVD-R x8 disc and after about 20 seconds the recording stopped and the Self Check message displayed.

I have mainly used TDK & Maxell DVD-R x4 discs but have also used Tesco branded DVD-R x8 discs without any problems. The x8 discs shouldnt have worked as the machine is only supposed to work with x4 rated discs. I only realised this when I started to investigate the problem.

I then recorded on a RAM discs with no problem. Panasonic & Maxell

As x4 discs are difficult to buy I dont know what to do next. I have a stack of x8 & x16 TDK discs but dont want keep trying these as it seems that they are incompatible.

Any suggestions as to why RAM works but DVD-R now seems to fail. Anyone with this machine have the same experience. Where can I source x4 discs that are known to work with the DMR E55 in the UK

Dusty or dirty lens? try some Dust Off spray and/or a lens cleaning disc. I have no problems using x16 discs with my ES15 or ES25