Going to cost your Mechy mate around £1k just for his survival and MIST. You will need another £800 or so on top of that for Compex. Without CompEx -forget it as a spark. You may get lucky, but you will need to be very, very lucky to get a pull in without it. Medical probably another £100.
Compex is not difficult - provided you work at it and use the time outside of the course to study what they give you.
Oh did I forget to mention accommodation on top if that? Add another bucket load of cash to it. 2 weeks dogs for you, 1 for your mate. You can cut the digs aspect by choosing a University town out of term time and taking student accommodation.
I don't know the rates exactly now, but the guys on the Culzean at present are getting less money now than companies were paying 10 years ago. Rotations ate often 3 on, 3 off also these days vs the 2 / 2 that was the norm for contractors.
The long and the short - the money is ok, but not as ok as it should be for the loss of your sovial and family life. You need to spend around £2k to get a foot in the door, and even then it's not guarenteed.
You are going to be 'green' for at least a year, so many companies will be reluctant to take you on as a new start. Times of year - Xmas and new year can be good for a start, as people phone in sick for that trip. Then it's quiet till april/may and will stay busy up till around October when it dies down again.
If you can afford the £2k, go for it - just be aware that it may be difficult to get a start at first. At least you have email now, rather than sending faxes ! Last squad I was in were 24 guys, almost 50% green hats - just depends on the roject and how busy things are.
You could however try the drilling companies. If things are picking up they will take you on as a trainee rig spark. Tough job, but it us an option.
Experience - heavy industry, petrochem etc will help. Again, you may face the Compex barrier for petrochem.