I'm with Durhamlad, working with a charity is pretty much the same as working anywhere. That will go a long way to making up for any gaps. Plus, you've got the "moving from America" excuse which will interest most people. Solicitors are fairly respected here so I would be surprised if you had a lot of trouble finding something.
Just remember that it can take an astoundingly long time for companies to organise the hiring process. Sometimes you won't hear anything for weeks, then they will call you out of the blue.
Also be aware that there is a shameful habit here of not telling you the result after you interview if you are not successful. I guess telling a relative stranger that they have failed over the phone is just too much for most English people, so they just ghost you. Combined with the glacially slow progress, it can be frustrating. You don't even know if you've been properly snubbed for months.
I'm going through a process now to work for a consultancy and the on-boarding process is nuts. Credit check, criminal records, addresses and employment for the last 5 years, weeks of investigation.