If a client has gone to the effort of instructing you to find an experienced professional, it is probably the case that they will be able to get a work permit. Most IT positions, other than the very Junior and those using purely legacy skills, are now recognized as being in shortage and thus applications for them do not need to be supported by proof the post has been advertised.
Where advertising is required, your client must show there are no suitable candidates from ‘the resident labour market’. In these circumstances, The work permit application will need to be supported by a letter from you detailing where you have advertised the position. Internet advertising may be deemed ‘acceptable’ where it can be shown that it is the most appropriate type of advertising for the desired target audience.
Where advertising is required, If you have not already advertised the position, the application may need to be delayed slightly while advertisements are run and the response is gauged.
If your client is a service company or software house that will employ the candidate to serve their own clients, then it will be necessary to show the authorities a copy of the contract between your client and their client(s). This requirement may cause initial concern, but your clients may rest assured that the terms of the contract will be kept confidential by the authorities (at workpermit.com we know of many instances where ‘price sensitive’ information (or, as verbose city folks would define it, Specific Unpublished Price Sensitive Information) has been given to Work Permits (UK) – and we know of no cases where this disclosure ‘leaked out’)