GBP vs EUR, what will happen?

Hello all!

We are a Spanish couple expatriated in UK. As of January, my contract is re-evaluated where we need to make an important decision: my company gives me the possibility to be paid either in EUR only, or GBP only or part of EUR and part of GBP.

The calculation is as followed:
- the salary (eg Protected content is calculated on an EUR base and converted to GBP
- To convert in GBP, they do not use the current exchange rate but the average of the past 6 months (july ˜til december), being more or less 0.806
- The would be Protected content * 0.806 = £806 salary
- From the £806, we could have a part in EUR and other in GBP (eg £600 to the EUR account and £400 to the GBP account) at the same rate 0.806. Basically HR doesnt want to bother in using the updated exchange rate but the one calculated previously.
- Knowning the current rate is 0.90, it would be a good deal as:
* company rate: £600 * (1/0. Protected content 744€
* market rate: £600 * (1/0.90) = 667€

So, the question is the following: is there anyone who has a good opinion on what could happen in the future with the Pound in Protected content ?
Is it going to raise or go down still?
Also, if we save Money, World you think it is better doing it in GBP or EUR?
What World you do in our case?

Thank you so much for your help