Quick question about selling leased property?

I own a flat which is leasehold, I am thinking of selling and was wondering if anyone could tell me if the there was a rule of thumb as to whether a management company will make any charges if I decide to go ahead, so I can add it into my moving costs.
I’m in UK.

Cheers
Also I got in touch with an independant HIP person to see if it would be cheaper than the estate agents quote, it came back cheaper but he said he wasn’t VAT registered. Is that normal? as I thought all UK businesses had to pay VAT?

Sell House Quick