Access for inspection & gas checks

Access

We have a very difficult tenant who sometimes communicates with us when it suits her. In particular, she has not been responding to requests for gas checks & inspections, although we know that she is fully aware that these need to be done at the moment. In a letter or email to her, can we say that "the gas engineer will call around on a particular date and time and if we do not hear from you prior to that (unless you let us know if not ok), we will assume that all is ok for us to let the engineer in ourselves?" The same would apply for the inspection. I think this may not be an acceptable route, but thought I would ask anyway.