Indeed, get the solicitor to make arrangements for you to see an expert (assuming a GP unless you've been seeing a specialist, I personally saw an orthoapedic surgeon as I had orthopaedic surgery).
To give an idea of timescale. I made the expert appointment in mid April, saw him in early June, solicitor received my medical records (3 hospitals + GP) a couple of weeks ago, sent last week to expert, now awaiting his report!
As you have now lost your job, the solicitor can arrange for advance payments for loss of earnings which will come out of the final settlement