Just to end this thread with an update on what I did.
After seeing that I was unable to remove the upper steering column without either removing lower dash or drilling a huge hole in the bulkhead I had a rethink.
I purchased a Puma steering column for not a lot of money. Knocked out the inner shaft and checked lower bearing. As expected it was perfect. I then carefully prised out the upper needle bearing that is encased in a rubber housing. This was fine but just needed packing with grease.
I then knocked out the inner shaft of my original column. Now at this point I encountered the only stumbling block of the job. Even with all the mounting brackets loosened, there isn't enough movement in the outer tube to be able to completely slide the inner shaft out. It either fouls on the chassis leg, or the shock turret. Luckily my front brake servo/mounting was only temporarily fitted with a couple of bolts. Once I removed this I was able to completely remove inner shaft. I removed old upper needle bearing and cleaned up the outer tube ready for the replacement upper bearing and inner shaft.
I covered the rubber housing of the upper needle bearing in grease and it tapped easily into place. I then slid the replacement shaft into the original outer tube and tapped home using a large rubber mallet. Replaced the circlip at bottom of column and tightened brackets. Job done. It's now smooth as butter with no play..