Well, looking over your settings, a few things stand out. Keeping in mind that I'm not sure exactly how you have this deployed (but I'm assuming it is as a trunk into 3CX).
PSTN ring thru line 1 should be NO (unless you really want the phone in the FXS socket to ring as well)
I'm not sure why you have the PSTN to SPA and SPA to PSTN gain, set so high. That is usually asking for audio problems, mostly echo. If levels are that low then there may be other issues with the phone line that you are over compensating for.
Is there a reason the the line in use voltage is that low? On a 48 volt phone line, I find that 30 volts seems to work just fine.
PSTN ring timeout is usually left at the default of 5 seconds. This is the amount of time, after the last ring burst, before the gateway decides that the PSTN ring has ceased.
I see you have the PSTN answer delay set to 3 seconds, which is the North America minimum for caller ID to work. I'm not sure what the minimum need to be for UK type caller ID. You could try increasing that a bit to see if that helps. You are sure that you have caller ID option on the line, right?
You didn't include the CID settings.
h2009 said:
I was hoping to find a better unit which can actually detect the settings.
I'm not sure that there is a gateway out there that will set itself. Most (from the ones I have dealt with) seem to come with North America settings and have to be manually customized for your particular country.