HM Land Registry Lease Registration

I need assistance registering a supplemental lease for a residential leasehold property with HM Land Registry. I require help preparing the necessary documents. I inherited the property in question 10 years ago from my uncle ... (Budget: £250 - £750 GBP, Jobs: Contract Management, Contracts, Legal, Legal Consultation, Legal Research, Legal Writing, Property Law, Property Management, Real Estate, Real Estate Management)