Just to let everyone know that at present the above institute offers one of the most cost effective ways of testing for Down's and open neural tube defects. The integrated test also identifies pregnancies at high risk of Edwards' syndrome. The combined test is the first stage of the integrated test - this is available on the NHS. Once you had this done make an appointment with the Wolfson Institute for a quadruple test (£80). They will analyse both test results together which will essentially become the integrated test.
I just had this done by them and was most satisfied with their services (for a mere £80). They also saved me nearly £300 [schock] by not going to the LUC.