Hi Everybody,
I'm giving my M300 a refurbishment. The oil level sight glasses were totally useless. Talked with sales at the 600 group. £9.95 plus vat plus postage by courier. Total cost £41.43 for 3. Tried to clean and repair my own but failed miserably.
After much searching on the net found "Harrison lubrication engineering – the home of the Nipple Shop". They are in Bolton Lancashire. Many of their parts are listed under Harrison numbers although I don't know if there is any association with the lathe manufacturer.
Sight level glass £2.19 plus vat plus postage. £12.08 for 3 and they arrived the next day.

Perfect fit, excellent value and really put a sparkle on the refurbishment.
Len