Had a query ref upgrading fixed heating thermostat to a portable wireless one. Heating Controls Online (HCO) advised on the best solution in a series of e-mail exchanges and I ordered their suggested solution. Kit arrived in 1 working day via FedEx, despite only ordering Routine delivery. I had a subsequent query ref correct wiring and the HCO team responded immediately with the solution, advising me of the correct terminations. I followed their guidance and the new system was up and running in a hour. Excellent customer engagement, Service and response times. On a scale of 1-5, I give them 6!