The real world experience in setting up the first superficial hyperthermia service using wIRA in the UK and a proposal of a prospective pilot study (ThermoRad) to assess the effectiveness and safety profile of adding superficial hyperthermia to palliative radiotherapy in locally advanced or recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) or cutaneous squamous cell carcinoma (cSCC) not suitable for radical treatment