Though they are making great progress with acknowledging and changing processes and procedures for the greater good, I am still surprised that a company of 20 years is not bigger and has more business than they do. In my opinion, and I think/hope you know this, your office location is the problem. If you want to expand and get more talent, you "have" to open a office in London or abroad.
Do consider moving into more software areas.
They don't pay very well, but this is most probably due to the outside of London location.
You have or had a graduate programme, take care of them and nurture them to success, pair them up with a senior or mid-level employee to get them up to speed quickly, don't just give them a manual or tell them to do online courses. You have to mentor them and guide them. Everyone has to start somewhere.
You get the impression that finances are really tight, though I don't think that is the case, loosen up a little, no I'm not saying you should throw money away, but it doesn't give employees a good picture.