Hi, I'm Dr Steve, I realize you asked for a vet who could advise f an emergency clinic in Chiswick in London and unfortunately I am unable to do that, but I would recommend googling that and if that gives no results using a phone book, perhaps yellow pages or pages that offer advertising of businesses and finding one on your own. SOme vet clinics may not advertise that they are an emergency clinic but many clinics, especially in areas with no er services, offer after hours care just by calling their regular number and they often answer themselves or have an answering service. My concern is that it may be quite some time until a vet with this information in justanswer may log in and it may be too late when thatoccurs. With exposure to this mouse bait, time is important and it would be ebst to find a vet right away and not have tl awit for this specific information. I am going to try to google for you and get back to you in just a few minutes either way. I hope this has helped. If it has would you please click the submit button so i may receive credit for my answer. I will be right back. Thanks for using just answer and good luck.