Here's what I got:

1- Freezing chestnuts: wash the nuts, cover with water, bring to the boil Drain and peel. pack in rigid containers. Can be used to supplement raw chestnuts in recipes or can be cooked and frozen as puree for soups and sweets.

2- Chestnuts in syrup:
225g / 8oz granulated sugar
225g / 8oz glucose
180ml water
375g / 12oz whole chestnuts, peeled and skinned (weight after preparation) OR 1 x 439g can of chestnuts, drained (for everyone not so lucky as Martin)
a few drops of vanilla essence.

Put sugar, glucose and water in a pan and heat gently until sugars dissolve; bring to the boil.
Remove from heat, add chestnuts and bring to the boil again.
Remove from the heat, cover and leave overnight, preferably in a warm place.
On the second day, re-boil the chestnuts and syrup in the pan without the lid.
Remove from the heat, cover and again leave overnight.
oN THE THIRD DAY, ADD 6-9 drops of Vanilla essence and repeat the boiling process as above.Warm some 500g /1lb bottling jars in the oven. fill jars with chestnuts and cover with syrup. Seal the jars.

3- Candied chestnuts:

600g / 1lb 5oz fresh chestnuts, peeled
water to cover
225g / 8oz glucose
225g / 8oz sugar
a few drops of vanilla essence

Put the chestnuts in a large pan with enough water to cover. Bring to the boil, then reduce the heat and simmer for 20 mins or until just tender. DO NOT OVERCOOK AS THEY WILL DISINTERGRATE DURING CANDYING PROCESS.
Drain well, reserving 150ml of cooking liquor. Pour this in to a pan, add glucose and sugar and stir over a gentle heat until dissolved.
Add chestnuts and bring to the boil, remove from heat, cover and leave somewhere warm (airing cupboard?) for 24hours.
Next day, uncover the pan and bring back to the boil. Remove from the heat and leave for another 24 hours. Repeat next day, adding vanillla essence before boiling, then remove pan from the heat.
Using a slotted spon, transfer the chestnuts to a wire rach placed over a tray. Leave to dry in a warm place for 2-3 days until the chestnuts are no longer sticky. Pack them in cardboard or wooden boxes between layers of waxed paper.

PHEW!

I suspect you were after savoury ways of preserving more so, but this is all I could find. Hopefully you have freezer space if this is the case. Unless anyone else comes up with something (I'm sure EarthBabe will!!)