Thanks everyone for your input, all useful stuff. Brian and Dicky, I tried The Service Centre as I have used them in the past but, regretably, I didn't get farther than "we don't deal with Lowrance or Eagle". Despite asking for a bit of advice, I got the same response. I then tried Greeham Regis and they were helpful but the person I really needed to speak to was absent. Hey ho! Then, on Brians recommendation, I called Navico who are the Lowrance agents and asked to be put through to the Service Dept as I generally find engineers more knowledgeable that sales people. He talked me through my problem and advised, as I had suspected, that my unit is obsolete, Eagle are not made any more and I can't get a replacement GPS module. I could get a compatible unit which might work but no guarantees.
Now I was able to make a decision, it's definitely a new toy! I decided on a Lowrance Hook Reveal, 9" and Navico obviously sell them but the engineer had a quick look on line and found that Force 4 have them at a discounted price with £100 off, bargain! I found this surprising as it is the latest bit of kit they do and the one recommended by the Navico engineer.and, again surprisingly, he had recommended NOT to go for the Triple Shot model which saved me about £60. Long story short, I am awaiting delivery. As usual the Club has come up trumps with advice and my problem is, hopefully, solved. I look forward to being able to see where I am going. Next challenge is transferring my marks, hopefully easy as they are both the same manufacturer.