Cache deleted

[Arthur Murray]

On occasion my internet or the bbc site is temp down and get_iplayer
is trying to update in the background at that very moment, fails, and
my tv.cache is deleted.  When get_iplayer next runs all programs are
listed as being new, which is rather frustrating.  Is there a reason
not to preserve the cache in this situation?

ie: In the get_links sub:

$xml = main::request_url_retry($ua, $url, 3, '.', "WARNING: Failed to
get programme index feed for $_ from iplayer site\n");
#  perhaps "return 1 if ($xml eq '');" if the 3 retries fail rather
than continuing to create a empty cache based on no data?
decode_entities($xml);