Decryption of truncated data?

[Pip Jones]

Is it possible to decrypt a data block which has the first 43 bytes 
missing?!

I inherited a wrapper script which was removing the PGP headers and 
footers using hard-coded string lengths, but after a GPG upgrade, the 
headers changed length and this part of the data was truncated. I've now 
got lots of small data blocks (around 1k) I need to decrypt.

I know this is unlikely due to the damaged structure of the encrypted 
data, CRCs, etc. but is there any way of recovering the partial 
remaining data?

thanks.