Thanks for your questions.
A person can divorce their spouse on the basis of a 5 year separation without their consent, but that person would still be required to have the divorce petition served upon them. Obviously you do not qualify under this ground for divorce yet so you would either have to rely on divorce based upon his unreasonable behaviour (which should not be to difficult given his previous conduct you refer to) or on the basis of a 2 year separation but you would need his consent to this. If he has been adulterous then you could also divorce on this ground.
You should request an address for service from the solicitors. If they do not have this then you may have to instruct a tracing agency on your behalf to trace an address for him
In terms of serving the divorce papers upon him the court would initially send the petition to the address you list, if he does not acknowledge receipt then you can either instruct the Court bailiffs to attend the address you have for him (ie. that which the previous solicitor used) or instruct a private enquiry agent/process server to do this for you. The court bailiffs would simply attend and see if he was there, a private process server would wait until he attends.
If you google "process servers" and your locality you will get a list of persons you can instruct.
Once they have served it upon him they will swear an affidavit of service and submit this to court as proof he has received the petition. The divorce can then proceed.
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