Did you need a mortgage to buy your house? If so, your solicitor is under an obligation to send your title deeds to the bank once registration is complete. I know from experience that banks start sending reminders after a certain length of time for the title deeds.
If not, well you could keep an eye on it yourself if you are worried. Ring the land registry ( but wait for at least 2 months after closing, as the deeds must be stamped first and only then lodged in the land registry and this can take up to 6 to 8 weeks) and ask. And if not lodged, ring your solicitor and ask why, and keep ringing.
Your solicitor does have an obligation to stamp and register, so it is unlikely that they won't do it.