Meet The Team.


Gemma Ollerton

Managing Director

Gemma joined GMS Services in 2000 carrying out general office duties.  After completing an NVQ in Business Administration and ISO audit training Gemma’s role changed to concentrate on logistics and Quality processes of the business as Office Manager, before becoming Logistics Director.

Gemma has years of experience of looking after the employees at GMS Services and in 2019 completed her CIPD Level 5 Diploma in Human Resource Management.  Gemma is passionate about the wellbeing of all employees at GMS and thrives to be an Employer of Choice.

Gemma is now the Managing Director, taking over from her Father, Howard Parry, who retired in October 2022.


Carl Ollerton

Technical Director

Carl started off his professional career by completing a mechanical engineering apprenticeship. He has worked in the commercial HVAC industry since 1999 and moved to the water treatment and legionella control side in 2005.

Carl has a strong mechanical background with many years of experience in conducting legionella risk assessments, water treatment programmes, commercial plumbing projects as well as consultancy and training of staff and customers.

Carl now oversees all our health and safety, staff training, new business technology and bid writing for new contracts and projects.


Craig Jenkinson

Mechanical Operations Manager

Craig joined GMS in 2006 as an apprentice plumber. Craig worked on commercial plumbing projects and specifically legionella remedial works.

Craig is also experienced and trained in legionella risk assessing and PPM activities associated to water hygiene and water treatment. He has successfully moved through the company to a senior role and now oversees all our mechanical projects.

Craig is responsible for the role out of any new mechanical projects and contracts that GMS obtain and is well respected by all our clients and the whole team working around him.


Stephen Parry

Contract Manager

Stephen joined GMS in 2007 as a water hygiene PPM technician. He has gain a wealth of experience as he has moved through the ranks of PPM technician, legionella risk assessor, contract supervisor to contract manager.

Stephen oversees our national contracts and has a wealth of knowledge in staff training and contract mobilisation.

Stephen manages a team that includes contract supervisors, contract coordinators, risk assessors and PPM technicians. He has a great relationship with his team and clients and works tirelessly to maintain the strong working relationships and service delivery standards our customers deserve and GMS demand.


Cath Dahl

Contract Coordinator

From a career change of over 13yrs in Sales Cath joined GMS in 2007 in an administration role. Her first role with GMS was an Auditor, overseeing all the Legionella Risk Assessments. She then became Senior Administration Assistant, and is now a Contract Coordinator for numerous clients.

She has developed new skills to help support the ongoing growth & success of GMS. Cath works closely with her Contract Manager to oversee a team of PPM Technicians and Risk Assessors and is well respected by all the team at GMS and the clients she supports.


Ben O’Berg

Contract Manager

Ben joined the GMS Team in 2013, although has worked with Health & Safety for over 25 Years. During his time with GMS Services, Ben has worked in various roles within the business, including all areas of PPM works and Risk Assessing.

In 2021, Ben joined the management team and oversees various contracts located in the North of England and Wales, where he has a close working relationship with the team as well as clients within his remit.



Kerry Houghton

Contract Coordinator

Find out how we can help you!

With our extensive experience in Legionella Risk Assessment Services & Water Treatment Services Contact us today to find out how we can help you.

Contact Us

Recruitment Drive 2024!

We are currently #recruiting for multiple positions to fulfil expansion for 2024. The focus of our recruitment is in North West England and the Midlands. Join a company who is focused on delivering high quality services to our clients whilst providing a flexible and supportive environment for our employees. We will invest in you to expand your… Read more »

VDI 2035 Training

Many thanks to Terry Harvey from Magnetic for the training session he delivered to our Management Team today. Who is the VDI? Taken from Magnetic’s website – link to page – Verein Deutscher Ingenieure (VDI) (English: Association of German Engineers) is an organization with over 150,000 engineers and natural scientists. More than 12,000 honorary… Read more »

Mental Fitness Workshop

Many thanks to Andrea Bellamy (MCIPD) of ABC HR for carrying out a #mentalfitness workshop for the team yesterday. This included a session from #stateofmind presented by Phil Veivers. The session was used to launch our Mental Health Workforce Strategy which included the launch of our mental health champions scheme and roll out of our (EAP) Employee Assist Programme.The session was received… Read more »

Meet The Team – Tom

I have been at GMS services Ltd for 11 months now working under my role as a water hygiene engineer. My daily tasks include carrying out PPM (planned preventative maintenance) taking water temperature from individual outlets in different areas, calorifiers checks, water tank inspections as well as expansion vessel and TMV servicing. I thoroughly enjoy… Read more »