I would see if they can have an engineer come out to meet with you to talk about placement and height of new service or requirements for underground if that is how it has to be done.
Then I would find a meter main that they approve of get install service cable meter main ground rods water bonding per NEC or local amendments and install a sub panel with main inside wherever works best and meets codes you can put it just about anywhere because of the OCPD in the meter main.
Once that passes I would find out if you can feed the old panel with your new panel or use it as a junction box worst case you may have to remove the old panel and use junction boxes.
When I do service upgrades I like the meter mains then I can go anywhere I want inside to feed a new or existing panel as long as it meets the inspectors approval. Here they allow me to get the new service inspected and connected with the meter main and all I have to do is call them back to inspect how I do the work inside. And customers are without power for a very short time. Once they cut the old service and connect the new service all they have to do is wait for me to run a feed from the meter main to a new or existing panel.
I did one they disconnected the old service and while they were connecting the new one I already had conduit and wire going from the meter main to the old panel and just had to disconnect the old service wire in the panel and connect it to the meter main feed a break the neutral ground bond flip a breaker in the meter main and they had power in about 20 min. Inspector comes back and gives the final approval.
Customers love it that they are not waiting around for an inspector and POCO reconnect sometimes not till late at night.
Please ask me about my special discount for people that shut up and stay out of my way! With Electricity there is the right way to do it and the dead way. Just because it works does not make it safe.