David, a medical doctor, and his wife Gwenyth, a teacher, spent 18 years in Nigeria, Chad and Sudan.  At a leprosy institution they developed a programme of reconstructive surgery and physiotherapy.  From this centre, in 1960 they began a medico-evangelistic outreach, selecting African missionaries, training them in simple but effective diagnosis and treatment, and deploying them in clinics around the shores and islands of the huge inland sea which is Lake Chad.  A floating theatre brought a surgical facility to the far-flung clinics.

On their return to UK with their two sons in 1976, David and Gwenyth continued to develop medical and missionary initiatives.  Active Service Trust was set up initially to provide a peaceful, residential environment where overseas workers, and those in ministry in the UK could regain their physical, mental and spiritual strength, and return into active ministry. 

From their base in the UK David and Gwenyth continued their ministry through various board memberships, Bible teaching and leadership training across various continents, and supporting key mission projects over the years.