Originally Posted by
heckenhocker
Thanks for clarifying the situation. I can understand that arriving at your hotel after 7pm (assumed from time of first post) after a long journey may mean you feel unable to return to the airport tonight. I often arrive "dead on my feet" and likely to make such a situation worse due to jet-lag-brain.
Long journey? Jet lag? OP flew in from Venice.

If OP was staying at a hotel with a concierge, how hard would it have been to arrange for someone to go to LHR and make the exchange.