Thanks for the replies Rusty Nuts and Kwackboy.
Rusty Nuts, when at rest engine not running but ignition on, display indicates 11.5v
Ignition off, 12.5v at battery terms.
I'll retest at the battery terms in the morning, ignition off, inition on and engine running at various revs and see what I get.
Kwackboy, from what you've said as regards rest voltage at battery and running voltage, it sounds like all is OK. Thanks for that.
Ref the battery charger ,it was used for a 12v 7Ah sla battery. Charger output at 12v is stated at 600mA. (Ansmann model ALCS2-24A).
I was just a bit concerned that the battery had been left for a long time without any charge going into it and it might have damaged it.
I'll do my checks tomorrow and post up the results.
Next thing for me to think about is optimate, oximiser or ctek for charging/conditioning.
Thanks again chaps, much appreciated.