Good RTC ADHD Clinics? Harrow Health is Driving Me Insane

So I got diagnosed a year ago when I was staying abroad with my family, then I had to get reassessed in the UK to get my meds here now that I'm back in London full time.

The whole process with Harrow Health took like 4 months which wasn't terrible at all because I had a 3 month stockpile that I made last. But holy shit, these guys are terrible at communication.

They reply to emails once a week, so when I take the time to write a lengthy email requesting or inquiring about something, the reply is usually short, concise, but takes several weeks to resolve if I have further issues. For example, they claimed to not receive my email containing all my blood pressure and weight readings (despite sending it to the same email and from the same email I always have) which meant I had to wait 3 weeks following my assessment to get my prescription, because they have a mess in their system.

Add the fact that they also sent me a text message that my "appointment has been cancelled" back in December, because I "did not provide sufficient information" which resulted in them terminating my assessment date, which turned out to be "an error that everyone patient received a text about".

Anyways, they're a mess and its impossible to ever get through to them as they just cut me off after 30mins of waiting if no one picks up the phone. I'm done with them.

I'm looking to switch to Dexamphetamines or Lisdexamphetamines as I've developed a tolerance to my current Methylphenidate dosage. Going any higher is not recommended, so I guess I'm stuck with meds that don't work on me anymore and a clinic that replies once a week if I'm lucky.

Anyone switched or have any recommendations of a clinic that actually functions? I'm based in London btw