My wife needs to go for her 12 week fetal medicine scan and the doctor practice she had a booking with just sent a message to say they are closed during the lock down, this is a rather important scan health wise any recommendations are welcome ?

Pregnancy: If your wife has no specific medical or OB issues and the scan is routine there is literature that finds no difference between outcomes between pregnancies without scans and those who get scanned. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1678458/. As such, probably lots more risk to get infection as opposed to waiting a month is really not an issue. If specific concern different story.

Usually fine to wait: The 12 week ultrasound scan is helpful but if your wife is feeling well, having no problems, & not in a high risk group (over 35, previous pregnancy problems, underlying medical condition like diabetes or heart problems, etc) it is not a problem to postpone it. That can be stressful to an expectant mother who is looking for reassurance; contact Dr office if problems arise