I've just discovered that I have exactly the same light in my workshop. I'll need help in getting the ladder down so I'll ask a mate to help. We can swap starters first and if that doesn't help, swap the tubes. I can get whatever needs replacing locally.
If you need low cost replacement fittings for bugger all (sometimes with working tubes etc) go down to the nearest council dump where they will probably have a shop that sells them....usually removed from various offices etc.
Shame you are not close by, I have 4 or 5 spare 5ft fittings, tubes and some 6ft tubes gathering dust in my garage
No worries. These are 5 foot jobies. I've been here 5 years and never had to replace one, so can't complain. It would make sense to keep a spare tube and starter as I have two.
Not the starter but the tube - my mate could tell before changing it. He explained to me how to tell, so all good now!