If you have a straightforward case IMHO you don't need a lawyer. Straightforward means you don't have any but's when you go through the requirement list. So income propf for 6 months- check, marriage papers- check, proof of cohabitation for 2 years, etc. I'd recommend being organised about it and compiling all your evidence in neat folders. I'd also recommend the priority service is money isn't an issue. I got the super priority service for an extra £800 and got the decision the next day, with the brp posted to me in a week or so. Not sure if you need to go to an appointment to submit your passport but this usually costs extra as the free slots are always full. There's so much anxiety already from just the application so to have the peace of mind in 1 day was worth it.