I decided to call the test results line at my local GP surgery, to ask for more detailed information, and I should have done that before as they were extremely helpful. The following morning I received a 7-page printout, with 37 results in all.
The first one was as expected for a BT carrier - the standard full blood count showing the red blood cell count and their distribution width to be "above the high reference limit", and the mean cell volume and cell haemoglobin level to be below it. There followed a bone profile, serum C reactive protein level, urea and electrolytes and liver test levels - a full page of seeming normality.
Next, serum ferritin level 187, serum prostate specific antigen level 1.9 and TDSH level 1.43, all within normal limits. Serum B12 was 266, so I guess no need for a supplement here. Hopefully the same with Serum vitamin B12 at 266? Serum B12/foliate level was 6.5. Haemoglobin A1c level 36.6, HbA1c level 5.5%.
Finally, on a subsequent separate test, Transferrin saturation index was 34%, serum transferrin level2.3g/l,Serum iron level 19.9, saturation of iron binding capacity 57.7, and UIBC 37.8.
That sounds quite comprehensive to me, although I have nothing to compare it with. Is there any important test which they may have missed?