Yes, only the technology appraisals (assessments of individual drugs, or closely related groups of drugs, for a specific condition) have legal force that means the NHS must fund them.
Interventional proceedures guidance can specify that an operaton can only be done as part of a clinical trial, not done at all, or done without restrictions. But it can't force the NHS to do it.
Clinical guidelines set out best practices for what can happen, but again can't enforce them. If a doctor or hospital goes against them they'd need to be able to explain why in the event of a complaint, but the recommendations aren't mandatory.
Apart from the NICE technology appraisals I don't think there's anything that sets out exactly what treatments the NHS must offer. It simply wouldn't be practical. For example there's a treatment my mum had a while ago - a 'proper treatment for a recognised illness' (and a real, diagnosable illnrss that can be seen on scans). The NHS doesn't offer it now because there was only 1 UK doctor who did it and he's retired. It's a niche specialty requiring dedicated equipment and nobody took over the service. They can't make somebody train.