Which Mondial 3.2 spark plugs to use?

I have been fighting with my 87 Mondial 3.2 (UK spec) coupe to find out what the rough running and loss of power) problem may be. After testing the spark wires, 2 of them along the bank nearest the rear seats are not firing and 1 along the bank nearest the rear bumper comes and goes when it feels like it. I changed both ignition modules and TDC (crank) sensor and still having problems though not as bad.
I need to check the distributors and the components inside but just cant get to the one nearest the the rear seats.
Its going on for a service tomorrow and will get them to take a look and see whet the problem is. As due maintenance i am having the sparks changed but really dont know what are the best ones to use for this car and year. The handbook mentions Champion A6G but thats 25 years ago. Any recommendations for the best I can use?
Thanks.
Peter

 

Thanks thats excellent, I will make sure i get 8 of the NGK DR8EIX (iridium) sparks.
Steve, I just couldnt squeeze between all those compact wires to find that screw along the bottom of the distributor cap although i know its there. The 2 at the top are fine to remove. I removed the inner wheel arch liner but still couldnt get access enough to bend my hands round. I ruined the gasket on the distributor cover that i did take off and was worried i would cause more damage trying to remove the wires and cut he ends off and re-connect. I wish i had more time to do it with patience but the rain here just wont stop in this damn country and the service appointment is tomorrow
The 2 coil modules made a big difference to the start up and now it doesnt stall. It doesnt start as it should but better than it was.
It looks like neither bank is fully working but at least neither one is completely dead.
Do you think it could be the spark leads or distributor and its components? If not what else could it be?

Many thanks, Peter.

 

Sorry Mike, I wrote Steves name by mistake
My coupe doesnt have that access panel which you have on your convertible. It would be so much easier.

 

Went to buy the NGK DR8EIX spark plugs and been told they are for motorcycles?

 

Halfords here in the UK only mention motorcycles for this spark plug. Is this right? Anyone else come across this?

 

Halfords here in the UK only mention motorcycles for this spark plug. Is this right? Anyone else come across this?

 

Good morning Mike, must be early at this hour
There's no doubt that they are the best as you said and I am buying a set today. Thanks for your advice and the link. I also looked at the NGK website and its exactly what they recommend as an upgrade.
I'm booked in for the service today but looks like another downpour here yet again and may have to postpone. The sparks are £10 here in the UK, approximately $15.50 USD. So much more expensive here

 

Sparks are now on their way, found a great deal online so i had to postpone the service till next week now. I will also be changing the spark plug wires, are there good ones to choose from and bad ones to avoid?
Thanks, Peter.