Hi David,
I had to strip out my 34 and I can confirm there is no inspection hatch. Even the fuel filler point is hidden under the wet locker floor. My tank was heavily contaminated. The only access was through the fuel sender unit area. Its a bit of a fiddle to get the sender unit out. Don’t force anything.  My drain valve was seized and couldn’t be removed in tact. I had to siphon the old fuel out.
When empty, I drilled the drain valve and washed out the tank as best you can. Hoovered the left over water, dropped a removable silica gel package into the tank and left it for a few weeks. Removed it and re-fuelled with heavily dosed diesel bug preventer. Seems to have done the job.