£400 sounds about right. If you have time, it's worth travelling somewhere cheaper in the UK to get these tests done.
I was quite lucky that I had a full medical check up (from my employer), this covered 90% of the tests required, so was able to share these blood test results with Eugenix. There were a few that were not on the list, and I got the rest done at Medical Diagnosis - they were reasonably priced (for London), the results were super quick, got those back within a few hours.