Are they newbuilds? On some development sale offs a general set of searches will be provided by the developer and it is quite commonplace to see an indemnity policy put in place to cover the fact that they are not flat specific and will be out of date. Some will still conduct individual local searches. It all depends on the set up.
Some of the searches do not need to be apartment specific if there is a site search which provides an acceptable result. It may be that an indemnity policy is needed if it is out of date though.
It can also depend on what your lender requires.
Have you had official written confirmation of instructions from the solicitor as they should set out fees and charges which are known about and likely.
If it is a development of properties (say a large complex of apartments) being sold there is often a pack available for legal advisors for the buyer and sometimes recommended legal advisers who have knowledge of the site and which can speed things up.
Difficult to say without knowing the circumstances.
One thing to watch out for, especially on purchasing new apartments is fees that are increasingly commonly charged to generate additional revenue such as engrossment fees (essentially for the seller's sols to provide final lease/transfer documentation for signature), Deed of Covenant fees, fees relating to management of a management company etc...
They are mostly vatable and can really add up, especially if engrossments of ground rent and service charge are also taken on completion. There may be other indemnity polices or charges and some lawyers charge extra fees as add ons for dealing with a leasehold property, mortgage, dealing with indemnity insurance etc...
I'd ask for as full a possible breakdown as possible early on.
Also make sure you are fully versed as to all the lease terms, especially for possible financial implications like fees payable if you sell the apartment - these can really add up!
It really can be worth paying a experienced professional, be it solicitor, licenced conveyancer, legal executive, paralegal - it is the skill of the professional which counts rather than the qualification and often, as per the old adage, you get what you pay for.