Regarding the Manchester base for DECs, the short answer is No! There is an internal queue miles long of pilots trying to get commands at MAN and the biggest danger you face as a captain there is being run over in the car park by someone trying to get your slot! It is inconceivable to me that any DECs will ever get a job there. The most likely base by far is LGW.
Regarding captain salaries, the UK deal is, within a few pounds, as follows:
Captain Basic of £104,747. You get paid 95% of that for the first 6 months but full pay after that. Sector pay is £34.97 (I think!). If you work on 430 sectors per year (varies by base) = 430 x £34.97 = £15,037.10. The Company pays 7% of basic (£7332.29) into your pension (there is a little more due to a smart pension rule but ignore that for now!). Therefore, the maximum you can put tax free into your pension is £32667.71. You also get performance related pay which is typically £2k-£3k a year if the company does well. You can also put £500 per month into the share schemes and most captains do that, but it is completely optional. You often get a further £3k worth of shares if the company is doing well - that will almost certainly happen again this year. After 5 years they are yours to cash-in at whatever the shares are worth then and the whole deal is tax free. There is no incremental pay, but after 2 years, you get 5% of your basic salary loyalty bonus paid annually on the anniversary of you joining, after 5 years 10% and after 10 years 15%. That carries on for as long as you remain an employee. Remember that once you earn over £100k in the UK you effectively get taxed at around 62% - therefore every captain does what he can to keep his salary below that using pension contributions.
There are therefore many variables so it is hard to say what anyone gets as they all put in different amounts into the pension and share schemes plus you cannot guarantee exactly how many sectors you will fly. To keep it simple, however, if you are a UK captain after the first 6 months, but before the loyalty bonus kicks in, putting nothing into the shares but just reducing your salary below £100k by pension contributions, flying 430 sectors a year, you can expect to take home £5,500 a month. If you put the full £40k (including company 7%) and fly 430 sectors a year with no share scheme contributions, you will earn very close to £120k a year. Take off your £32,667 into the pension fund and that leaves £87,117. That will give you £4877 per month. In addition you will still get your performance shares (£3k) and the performance payments etc if they happen. There is another slight oddity and that is, by union agreement, you get £56/month for leave payments - every little helps! I hope all that makes sense. It is not a clear picture but very logical if you plug the figures into you own circumstances depending on share payments and pension contributions.