Don't listen to John then, Phil. There are plenty of good and reliable models around Lincoln and nearby. Indeed I even worked with a couple of decent codhead models when I was living up in the Lincs/Notts area.
One of the most highly-rated models on this site used to live a short drive (or train journey) south of Lincoln, though I see she is now showing up under Notts so may have moved a little to the west, and there are scores of others with great reputations within easy travelling distance of the city.
If your work offer meets their expectations, you should have little difficulty sourcing suitable, reliable models to work with in the East Midlands.
Been there, done that, got the T-shirt, writing the book etc....
I discovered my 'Muse No.1' while studying at Lincoln Uni and my 'Muse No.3' studied there; both are artists who also modelled (before careers eventually got in the way) and being paid to model was not their primary goal in life.
One of the very few genuine six footer female models I have published was also a Lincoln Uni discovery. Coincidentally, after 12 years she tracked me down only the week before last (through an aquaintance on Friends Reunited, which was very big when we were at Uni together) to ask if I still had any of her old tearsheets. I do, and she's now a very happy bunny.
Many regional university cities, particularly if the uni has a strong Arts tradition, seem to be a great source of models.