Logstash 7.9.1-1 installation errors - service not found

Hi there,
Just tried re-installing logstash having removed it on an ubuntu server and had the following errors:

Get:1 https://artifacts.elastic.co/packages/7.x/apt stable/main amd64 logstash all 1:7.9.1-1 [159 MB]
Fetched 159 MB in 35s (4,555 kB/s)
Selecting previously unselected package logstash.
(Reading database ... 198511 files and directories currently installed.)
Preparing to unpack .../logstash_1%3a7.9.1-1_all.deb ...
Unpacking logstash (1:7.9.1-1) ...
Setting up logstash (1:7.9.1-1) ...
sed: can't read /etc/logstash/logstash.yml: No such file or directory
/etc/logstash/startup.options is not a file path
To manually specify a startup style, put the path to startup.options as the
first argument, followed by the startup style (sysv, upstart, systemd)
chmod: cannot access '/etc/logstash/startup.options': No such file or directory

Then when trying to start logstash, the service is not found.
Is this due to me manually removng things after removing it?

If so, how can I repair or fix things?
What's the best way to get back to a completly vanilla install?

Many thanks.

Does /etc/logstash exist and who owns it?

Yes - it does. Owned by root.
The /etc/logstash directory has a logstash.yml file and a conf.d directory present, and nothing more.

and yet it logs

can't read /etc/logstash/logstash.yml: No such file or directory

You are running the install as root, right?

Yes - correct.
I'm wondering if the problem exists because I removed a previous install with apt.

There seem to be various artefacts remaining which relate to the previous installation - I'd like to nuke everything and get back to a clean install of logstash if I can.

I would be tempted to run the install with 'strace -f -o /tmp/trace.txt ...' and see what errors it is getting when accessing those files under /etc/logstash.

Okay - will do.
I have to head out now - but i'll try this first thing tomorrow - thank you for your help!

In the end, I felt the server was no longer in a stable and reliable state, so I have rebuilt it and everything is working correctly again.

Thank you for taking the time to look at this and sorry I'm not able to give more insight in to what happened or why.

Kind regards,
John.