TM disk being unencrypted - lost from sight...

Hi.. I was unencrypting my TM back up disk volume (one of 3 on a 2TB My Passport) when the battery failed on the Macbook Pro. Doh. And now it doesnt show in disk utility or the TM Prefs menu as being in progress (it did before).

it DOES show when i do diskutil cs list... (see below). this is all above my competence and wondering if this forum can help me recover the TM volume?

Cheers, S

Logical Volume Group AE8BF148-2A35-4C1E-8731-CA8E11DC3ED2
| =========================================================
| Name: Pro TM
| Status: Online
| Size: 1000000000000 B (1000.0 GB)
| Free Space: 16777216 B (16.8 MB)
| |
| +-< Physical Volume 9865A799-800E-4FF5-B736-20F8173FF040
| | ----------------------------------------------------
| | Index: 0
| | Disk: disk1s3
| | Status: Online
| | Size: 1000000000000 B (1000.0 GB)
| |
| +-> Logical Volume Family A992B6D2-CDE0-42D5-B02A-8E72FEADDB82
| ----------------------------------------------------------
| Encryption Status: Locked
| Encryption Type: None
| Conversion Status: Converting
| Conversion Direction: backward
| Has Encrypted Extents: Yes
| Fully Secure: No
| Passphrase Required: No
| |
| +-> Logical Volume 0D3BE124-FF73-4920-8A7C-F78C83C28D0C
| ---------------------------------------------------
| Disk: -none-
| Status: Locked
| Size (Total): 999664451584 B (999.7 GB)
| Conversion Progress: -none-
| Revertible: Yes (unlock and decryption required)
| LV Name: Pro TM
| Content Hint: Apple_HFS
|
+-- Logical Volume Group CFBA536C-50D3-40EF-B8B0-A8A244731F13
=========================================================
Name: Air TM
Status: Online
Size: 399731564544 B (399.7 GB)
Free Space: 16777216 B (16.8 MB)
|
+-< Physical Volume 80B4110B-6904-4252-96A4-2158862290B3
| ----------------------------------------------------
| Index: 0
| Disk: disk1s5
| Status: Online
| Size: 399731564544 B (399.7 GB)
|
+-> Logical Volume Family ECDD53B8-A03C-4E59-94A4-D0C9965851C3
----------------------------------------------------------
Encryption Status: Unlocked
Encryption Type: AES-XTS
Conversion Status: Complete
Conversion Direction: -none-
Has Encrypted Extents: Yes
Fully Secure: Yes
Passphrase Required: Yes
|
+-> Logical Volume 5CA476B1-2C13-4436-ABF1-A283641CC67D
---------------------------------------------------
Disk: disk2
Status: Online
Size (Total): 399396016128 B (399.4 GB)
Conversion Progress: -none-
Revertible: Yes (unlock and decryption required)
LV Name: Air TM
Volume Name: Air TM
Content Hint: Apple_HFS

thanks - will try that!