Thank you for your question and patience, I’m Tom and I’ll try to help you.
I would not be too worried about the length of time it has taken since you have submitted your application. It is not uncommon for it to take 3-4 months for them to decide the application.
All you can do is request they expedite the application, whether they will be able to or not depends on how many applications they have at the moment.
You are free to withdraw the application but I consider that this would be unwise the circumstances. The reason for this is that if she withdrew and then attempted to enter the UK on a visit visa the entry clearance officers would be aware that she has recently made an application for a spouse visa to live permanently in the UK.
This would mean that it would likely that she would be refused entry on the basis that the entry clearance officers would suspect that she might seek to stay in the UK beyond the expiry of her visit visas. It happens quite often that they refuse on this basis.
My view is that if you have proved she meets the eligibility criteria in your application then the best option would be to wait a little longer until the application is determined. If the application was uncontroversial and contained all the necessary supporting documentation then I would normally expect them to decide the application within 3 months (so, sometime in July)).
The lack of communication from the home office is fairly typical, they consider that they are there to simply determine the application on the basis of the information contained in the application and the supporting evidence provided. It’s very frustrating of course, but it’s simply the system that applicants have to deal with (and I am very sympathetic to your view).
My goal is to provide you with a good service. If you feel you have received anything less, please reply back as I am happy to address follow-up issues specifically relating to your question.