SR44 batteries. Which is the best make?

My virtually unused LX (5344139) hasn't had a battery change for a long time.
It might even have the same ones that were in it when I bought it from London
camera exchange in 2008 for the bargain price of £169 (incl winder, which had
never been removed so the baseplate still has the protective film).
The batteries measure 1.57 volts, and looked ok but when I rubbed them
down my dark blue tee-shirt they left a slighty 'dusty' smear, so I think it's
time for some new ones.

Where do people get their silver oxide 1.5V batteries from ?. I have read somwhere
that ?Renata are the best ones to get. My MX has a single 3V battery but the LX has
two x 1.5V ones. I assume they are interchangeable.

Renata are a Swiss company. 'Swiss' and 'quality' seem to go together in the context of manufactured goods so I shouldn't imagine you'd go far wrong with Renata batteries. Check the capacity of the battery and compare with other brands though...most expensive isn't always longest lasting when it comes to batteries.

Your batteries have done really well to be still reading 1.57 volts after more than a decade...this will have saved them from leaking.

You could also consider using a single lithium 3v battery ref: 1/3N / 2L76 / CR11108 in place of the pair of SR44...more expensive but will last longer and with a much flatter voltage discharge curve (more Oomph for longer). Check first with someone in the trade who has done this...doubt there will be a problem but i personally have not tried it only read about other people using this replacement but for other applications.

Some of the instructions for the MX actually state do not use Lithium batteries. The LX might be the same, so I'd stick with silver oxide. I'm not sure why Lithium are not recommended, but it might be something to do with either them running hotter or maybe gases given off.

Oh well...disregard my last in the light of John's advice!

Better safe than sorry.